To provide a torque limiting device suppressing heat generation and deposition due to a slide of a friction plate.

A torque limiting device includes a pressurization part which adds pressing force for making a friction plate interposed between an input member 3 and an output member 6 generate frictional force needed for torque transmission and a sense mechanism for generating mechanical displacement in a leaving direction with transmitted torque, and causes the friction plate to slip on sensing excessive torque. The pressurization part is provided with a groove having two deep and shallow stages and a ball capable of freely moving in the groove so as to provide a reset mechanism such that the ball partially projects from the groove when in the shallow groove to add the pressing force to the pressurization part and sinks wholly in the deep groove when in the deep groove to add no pressing force to the pressurization part. Consequently, the friction plate becomes completely free to prevent transmission of excessive torque and burning of the friction plate.