To provide a clutch adjusting alarm device which supplies low pressure air from an air vessel to an actuator of a clutch mechanism through a pressure control valve, and discriminates an adjusting timing from operation of a rod of the actuator.

A clutch stroke sensor 5 senses a position of a rod 9 of an actuator 6 which connects and disconnects a clutch mechanism A. A pressure control valve 4 is operated for supplying pressurized air to the actuator 6. Also provided are a return spring 14 of a clutch lever 13, and a clutch spring 29 which presses a pressure plate 23 against a clutch plate 24. When a margin measurement starting switch 17 is operated, the pressurized air having force stronger than that of the return spring 14 and weaker than that of the clutch spring 29 is supplied based on an electronic control unit 3 to the actuator 6 through the pressure control valve 4. An alarm 2 is started when difference between a return position of the rod 9 which is a sensed value of the clutch stroke sensor and a stopping position of the rod 9 is a specified value or lower.