Earphone

1. An earphone characterized in that it comprises:

a tubular barrel having first and second ends opposite to each other along an axis of the barrel, the first end thereof insertable in an ear canal;

a transmission element that is provided on a part of a side of the barrel between the first and second ends of the barrel, has a part thereof being in contact with a tragus while the barrel is inserted in the ear canal and has a built-in electroacoustic conversion element configured to generate an acoustic vibration in response to an electrical signal;

a vibration element provided on an inner wall of the barrel and configured to vibrate in reaction to the acoustic vibration from the electroacoustic conversion element; and a biosensor, wherein

the transmission element has an extension extending from the side of the barrel to a direction orthogonal to the axis of the barrel, and the electroacoustic conversion element is provided on the extension via a joining element surrounding a whole circumference of a surface of the electroacoustic conversion element along the direction orthogonal to the axis of the barrel.

2. The earphone according to claim 1 , wherein the biosensor is provided on the barrel.

3. The earphone according to claim 1 , wherein the vibration element is provided closer to either one of the first end or the second end of the barrel.

4. The earphone according to claim 1 , wherein the vibration element is provided to separate a space in the barrel, and a part of the vibration element can move to separate and connect the space in the barrel.

5. The earphone according to claim 4 , wherein the second end of the barrel is rotatable around an axis along a penetrating direction of a through port of the barrel, and rotation of the second end of the barrel allows a part of the vibration element to move.

6. The earphone according to claim 1 , wherein the vibration element has a shape formed by combining a triangular pyramid part having a gap inside thereof and a cylindrical part extending from a vertex of the triangular pyramid part, and an inner space of the triangular pyramid part and an inner space of the cylindrical part are connected.

7. The earphone according to claim 1 , wherein the transmission element is provided with an elastically deformable hooking element to be hooked to an auricle.

8. The earphone according to claim 1 , wherein the vibration element is attached to the inner circumferential wall of the barrel via a hinge and is configured to move about the hinge to open and close a through port of the barrel.

9. The earphone according to claim 1 , wherein the second end of the barrel is rotatable around an axis along a penetrating direction of a through port of the barrel, and rotation of the second end of the barrel allows a part of the vibration element to move to open and close a through port of the barrel according to a rotation angle of the other end of the barrel.

10. The earphone according to claim 1 , wherein

the vibration element has a shape formed by combining a triangular pyramid part and a cylindrical part extending from a vertex of the triangular pyramid part, and an inner space of the triangular pyramid part and an inner space of the cylindrical part are connected, and

an inner space is formed between an outer circumferential surface of the cylindrical part and the inner circumferential wall of the barrel over a substantially entire length of the cylindrical part.