Golf club shaft

1. A golf club shaft, composed of a laminate of prepregs made of a fiber reinforced resin, wherein a weight of a unit length of said golf club shaft in an axial direction thereof is set to not less than 0.25 g/cm nor more than 0.60 g/cm; and if tensile moduli of elasticity of all of said reinforcing fibers of said prepregs of a straight layer, which are parallel with said axial direction of said golf club shaft, are sequentially denoted by N1, N2, . . . Nn in the order from an innermost layer of said laminate to an outermost layer thereof, then

N1≧N2≧Nn and N1>Nn is established in a range at least 10% of a whole length of said golf club shaft, wherein n is an integer not less than 3, and wherein at least three different prepreg layers each having different moduli of elasticity are present of said prepregs which form a straight layer with fibers parallel with said axial direction of said golf club shaft.

2. The golf club shaft according to claim 1 , having 3-8 straight layers of which said tensile moduli of elasticity of said reinforcing fibers are different from each other.

3. The golf club shaft according to claim 1 , wherein said reinforcing fibers of said prepreg of said straight layer are carbon fibers.

4. The golf club shaft according to claim 1 , wherein said reinforcing fibers of said outermost prepreg of said straight layer are pitch-based carbon fibers.

5. The golf club shaft according to claim 1 , wherein a ratio of said straight layer, of which said reinforcing fibers are pitch-based carbon fibers, is not less than 5 wt % nor more than 60 wt % of all straight layers.

6. The golf club shaft according to claim 1 , wherein N1≧N2≧ . . . Nn and N1>Nn is established in a range at least 25% of said whole length of said golf club shaft.

7. The golf club shaft according to claim 1 , wherein said N1≧N2≧ . . . Nn and N1>Nn is established in a range not less than 50% nor more than 100% of said whole length of said golf club shaft.

8. The golf club shaft according to claim 1 , wherein said tensile moduli of elasticity of said reinforcing fibers of said prepregs of said straight layer are different from one another; and a difference between said tensile moduli of elasticity of said reinforcing fibers of said adjacent prepregs of said straight layer is not less than 2000 kgf/mm 2 nor more than 30000 kgf/mm 2 .

9. The golf club shaft according to claim 1 , wherein a total number of said prepreg layers is not less than three nor more than twelve.

10. The golf club shaft according to claim 1 , wherein the number of plies of said each prepreg is not less than one nor more than two.

11. A golf club shaft, composed of a laminate of prepregs made of a fiber reinforced resin,

wherein a weight of a unit length of said golf club shaft in an axial direction thereof is set to not less than 0.25 g/cm nor more than 0.60 g/cm; and if tensile moduli of elasticity of all of said reinforcing fibers of said prepregs of a straight layer, which are parallel with said axial direction of said golf club shaft, are sequentially denoted by N1, N2, . . . Nn in the order from an innermost layer of said laminate to an outermost layer thereof, then

N1≧N2≧ Nn and N1>Nn is established in a range at least 10% of a whole length of said golf club shaft, wherein n is an integer not less than 3, wherein a tensile modulus of elasticity of a reinforcing fiber of an outermost prepreg of said straight layer is not less than 5000 kgf/mm 2 nor more than 30000 kgf/mm 2 , and wherein at least three different prepreg layers each having different moduli of elasticity are present of said prepregs which form a straight layer with fibers parallel with said axial direction of said golf club shaft.

12. The golf club shaft according to claim 11 , having 3-8 straight layers of which said tensile moduli of elasticity of said reinforcing fibers are different from each other.

13. The golf club shaft according to claim 11 , wherein said reinforcing fibers of said prepreg of said straight layer are carbon fibers.

14. The golf club shaft according to claim 11 , wherein said reinforcing fibers of said outermost prepreg of said straight layer are pitch-based carbon fibers.

15. The golf club shaft according to claim 11 , wherein a ratio of said straight layer, of which said reinforcing fibers are pitch-based carbon fibers, is not less than 5 wt % nor more than 60 wt % of all straight layers.

16. The golf club shaft according to claim 11 , wherein N1≧N2≧ . . . Nn and N1>Nn is established in a range at least 25% of said whole length of said golf club shaft.

17. The golf club shaft according to claim 11 , wherein said N1≧N2≧ . . . Nn and N1>Nn is established in a range not less than 50% nor more than 100% of said whole length of said golf club shaft.

18. The golf club shaft according to claim 11 , wherein said tensile moduli of elasticity of said reinforcing fibers of said prepregs of said straight layer are different from one another; and a difference between said tensile moduli of elasticity of said reinforcing fibers of said adjacent prepregs of said straight layer is not less than 2000 kgf/mm 2 nor more than 30000 kgf/mm 2 .

19. The golf club shaft according to claim 11 , wherein a total number of said prepreg layers is not less than three nor more than twelve.

20. The golf club shaft according to claim 11 , wherein the number of plies of said each prepreg is not less than one nor more than two.