To provide an oscillation unit for a hydraulic shock absorber capable of correcting a shift to allow accurate measurement, even when a lower end part of the hydraulic shock absorber generates slightly the axial shift with respect to a lower side attaching part.

This oscillation unit is constituted of an oscillator 2, a lower table 3 moved vertically by oscillation by the oscillator 2, a universal joint 30 for connecting the lower table 3 and the oscillator 2, a regulation member 31 for regulating motion of the universal joint 30, a lower side attaching part for attaching the lower end part of the hydraulic shock absorber 6 onto the lower table 3, and an upper attaching part 8 attached to position a tip part of a piston rod 7 projected and retracted from the hydraulic shock absorber 6.