To provide a torque limiting mechanism, a drive unit and a robot system capable of controlling a torque more stably.

A torque limiting mechanism capable of transmitting a torque of a rotary drive shaft to a driven shaft includes: a transmission part that has a second surface which comes into contact with at least part of a first surface of a rotating shaft that is at least one of the rotary drive shaft and driven shaft, and transmits the torque of the rotary drive shaft to the driven shaft when the second surface thereof comes into contact with at least part of the first surface with a force applied in a direction different from an axial direction of the rotating shaft; and a suppression part that suppresses a change in a state of a contact surface that is at least one of the first surface and the second surface.