To provide a device of inspecting a buffer for reducing the labor of a worker or a burden thereon while sharply shortening an inspection time for measuring damping force characteristics.

The device includes: a fixing support for supporting a buffer with one end side fixed; a rotating nut 35 rotatably supported and imparted with torque by the operation of a servomotor 29; a movable ball screw 37 non-rotatably mounted while being fit into the rotating nut 35 so as to be threaded to perform rectilinear motion according to the rotation of the rotating nut 35; a movable holder for holding the buffer at the other end side while being synchronized with the rectilinear motion of the ball screw 37; a vibration control means for causing the ball screw 37 to perform rectilinear reciprocation at a prescribed amplitude centering around a reference position by alternating the normal rotation and reverse rotation of the servomotor 29 to impart vibration to the buffer at the other end side via the movable holder; and an assist mechanism 43 assisting the rectilinear motion of the ball screw 37.