A robot trapping detecting device, mainly uses a shaft body to drive a convex body to rotate, and a convex portion is disposed around the convex body, so when a binding surface of a binding body is touched to the convex body and the convex body is rotated to the disposing position of the convex portion, the binding body is driven upward, and then, when the convex body is rotated to a position other than the disposing position of the convex portion, the binding body is driven downward, so that a sensed body disposed on a linking component is driven up and down by the linking component, and a sensing body senses a displacement change of the sensed body to determine whether a robot has stopped moving.