To provide a tool position detecting device capable of quickly detecting the tip position of a tool.

The tool position detecting device for detecting the tip position of the tool disposed on a working means moving in Z-axis direction orthogonal to a holding surface of a chuck table holding a workpiece and working the workpiece includes: a base placed on the holding surface of the chuck table; a touch sensor fixed on the base and including on the upper surface thereof an abutting part abutting on the tip of the tool; an optical sensor including a light emitting element and a light receiving element disposed on the base so as to embrace the touch sensor with an optical axis connecting the light emitting element and the light receiving element with each other being disposed so as to be orthogonal to the Z-axis direction and to get away by a predetermined distance upward from the abutting part of the touch sensor; a first output means outputting an electric signal when the tip of the tool intercepts the optical axis of the optical sensor; and a second output means outputting an electric signal when the tip of the tool abuts on the abutting part of the touch sensor.