Abstract: A torque limiter which can detect torque of both opening and closing of a valve and in which different torque values for opening and closing of the valve can be easily set. The torque limiter is provided with a torque arm having a connection section which is connected to a drive side gear and an intermediate gear and also having an arm section projecting from the connection section; an open side spring portion and a closure side spring means which apply spring force balancing with force acting, in proportion to torque of a load in opening and closing operation of the valve, in the direction of a tangential line at the meshing point of the intermediate gear; an open side torque detection switch and a closure side torque detection switch which are, when torque of a load in opening and closing operation of the valve exceeds a predetermined value, operated by the arm section; and a torque limiter shaft passed through the open and closure side spring portion.