Medical long body

While maintaining the flexibility to provide a medical long body that can improve operability anisotropic torque transmission performance by the rotational direction minimizing it. A medical long body having a proximal shaft extending spirally slit at least a portion (61) is formed by the axial direction (X) (60), proximal shaft (60), provided with a helix angle of inclination (alpha) is different from the site is the angle in the extending direction of the helical slit (61) to its section perpendicular to the axial direction (X), one of the opposing surfaces forming the slits (61) ( 100), the angle of the slits (61) with a spiral inclination angle (alpha) is formed a step portion changes locally (102), on the other opposed surface (110), the helical slits (61) It is abutment step portion (102) abuts when proximal shaft direction (60) is twisted to solve (112) is formed, the axis length in the direction (X) of the step portion (102) (L3 ) is, at the site helix angle of inclination (alpha) is relatively large It is longer than the old site.