To provide a tactile sensor probe for making thin an insertion part.

A sensor element 15 by a piezoelectric vibrator where a sensor surface is exposed is provided at the tip side part of a flexible insertion part 2, a self-excitation oscillation circuit 20 that is located at the rear side of and near the sensor element 15 and is turned into an integrated circuit is provided in the insertion part 2, the self-excitation oscillation circuit 20 is mounted to a flexible substrate 23 the flexible substrate 23 allows the self-excitation circuit 20 to be divided into a plurality of circuit parts and circuit parts 21 and 22 to be dispersed and mounted and at the same time, allows them to be arranged inside the insertion part 2, and the width of the flexible substrate 23 between the dispersed circuit parts 21 and 22 is smaller than the circuit parts 21 and 22.