To provide a stroke inspecting device for a spindle tool clamper of a machine tool, having improved working efficiency and measuring accuracy and offering superior working safety and working environment.

The stroke inspecting device for the tool clamper of the machine tool having the tool clamper for clamping a tool holder abutting on a tapered hole formed in the end of a spindle comprises a holder 2 having a tapered portion 3 fittable to the inner periphery face of the tapered hole of the spindle and a through-hole 5, a shaft 10 slidably fitted into the through-hole 5 with its end 11a protruded from an end face 3a of the tapered portion 3 and adapted to abut on the end of the tool clamper, a depth gauge 30 having a measurement terminal 31 arranged on the holder 2 extending to the direction of an axial center with its end 31a adapted to abut on the shaft 10, and a compression coil spring 25 for energizing the shaft 10 to the direction of protrusion from the end face 3a of the tapered portion 3.