Operation device

1. An operation device for use by a user by holding in one hand, comprising:

a thumb operating area defined on a surface of an enclosure of the operation device, where an operation member to be operated by the user, using his/her thumb, while holding the operation device is provided;

an inclination operation member including a stick part projecting from the thumb operating area, for being operated by the user by inclining the stick part, using the thumb; and

a first operation button provided on the surface of the enclosure in a position opposed to the thumb operating area, being capable of being pressed by the user, using another finger, in a direction intersecting a direction toward the inclination operation member,

wherein said thumb operating area comprises a first partial area and a second partial area, the first partial area includes an inclined surface which is inclined away from said second partial area, and the inclination operation member is formed in said first partial area and projects in a direction orthogonal to the inclined surface.

2. The operation device according to claim 1 , wherein the first operation button is capable of being pressed in a direction toward a grip portion on the enclosure, which is gripped by the user, using a palm.

3. The operation device according to claim 1 , wherein the first operation button is a button capable of producing an output as a function of an amount by which the user presses the operation button.

4. The operation device according to claim 1 , wherein:

the thumb operating area is an area extending in a longitudinal direction of the enclosure,

the first partial area is defined on a side opposite from a grip portion on the enclosure to be gripped by the user, using a palm, and the second partial area is defined on a side of the grip portion, and

a direction designation button for use by the user to designate a direction is provided in the second partial area.

5. The operation device according to claim 4 , wherein the first operation button is provided in a position opposed to a boundary position between the first partial area and the second partial area.

6. The operation device according to claim 1 , wherein said operation device is narrower at a middle portion as compared to a front end and a back end of the device.

7. The operation device according to claim 1 wherein a second operation button is located below said inclination operation member on the elongated operation device outside of the thumb operating area.

8. The operation device according to claim 1 , wherein a third operation button is positioned adjacent to the first operation button.

9. The operation device according to claim 7 , wherein said second operation button is a power button.

10. The operation device according to claim 4 , wherein the first partial area and the second partial area are linearly aligned with a lengthwise direction of the operation device.

11. The operation device according to claim 10 , wherein said inclination operating member is located on said first partial area in between said second partial area and a top of said operation device.

12. The operation device according to claim 10 , wherein said first partial area is inclined toward a top part of said operation device.

13. An operation device for use by a user by holding in one hand, comprising:

a thumb operating area defined on a surface of an enclosure of the operation device, where an operation member to be operated by the user, using his/her thumb, while holding the operation device is provided;

an inclination operation member including a stick part projecting from the thumb operating area, for being operated by the user by inclining the stick part, using the thumb; and

a first operation button provided on the surface of the enclosure in a position opposed to the thumb operating area, being capable of being pressed by the user, using another finger, in a direction intersecting a direction toward the inclination operation member,

wherein said thumb operating area has a first surface and a second surface, and wherein said first is surface is substantially not parallel with said second surface.

14. The operation device according to claim 13 , wherein said inclination operating member is located on said first surface.

15. The operation device according to claim 14 , wherein said first surface is inclined toward a top part of said operation device.

16. An operation device for use by a user by holding in one hand, comprising:

a thumb operating area defined on a surface of an enclosure of the operation device, where an operation member to be operated by the user, using his/her thumb, while holding the operation device is provided;

an inclination operation member including a stick part projecting from the thumb operating area, for being operated by the user by inclining the stick part, using the thumb;

a first operation button provided on the surface of the enclosure in a position opposed to the thumb operating area, being capable of being pressed by the user, using another finger, in a direction intersecting a direction toward the inclination operation member; and

a first direction designation button, a second direction designation button, a third direction designation button and a fourth direction designation button, each located in said thumb operating area,

wherein said first direction designation button, second direction designation button, third direction designation button and fourth direction designation button are positioned so as to be formed below the inclination operation member.

17. The operation device according to claim 16 , wherein said first direction designation button, second direction designation button, third direction designation button and fourth direction designation button positioned so as to be in a cross-like pattern.