To accumulate and release a load with a simple mechanism, in an automatic interrupting device for a friction clutch for shut off of a clutch in a transmission by energizing a load accumulated in a load accumulating means.

Normal turning effort of a motor 1 is decelerated through decelerating means 9, 13, a piston rod 4a of a hydraulic master cylinder 2 is axially moved by axial direction movement converting means 10, 12, and thereby, a friction clutch is shut off. When the friction clutch is connected by rotating the motor 1 in the reverse direction, turning force of the motor 1 and repulsive force of a spring in the friction clutch are accumulated as a load in load accumulating means 16, 18. When the motor 1 is normally rotated, the accumulated load is emitted. A link mechanism mentioned above is formed by a toggle device composed of crank arm 10, a piston rod 4a, a link 21 which is rotatably connected to the load accumulating means 16, 18 through a first connecting part 20, and a second connecting part 12 which is rotatably connected to them.