Abstract: An arm position control device for use in an industrial robot which comprises: a support body; a rotary arm rotatably mounted on the support body for rotation towed one of clockwise and counterclockwise deviation zones from a home position within a permissible angular extent; a home position sensor fixedly attached to the support body to identify home position of the rotary arm; a limit sensor fixedly secured to the support body with a predetermined angular spacing from the home position sensor to detect movement of the rotary arm beyond the permissible angular extent; a sensor actuator rotatable with the rotary arm as a unit for keeping the home position sensor interrupted when the rotary arm lies in the clockwise deviation zone, for making the home position sensor released when the rotary arm lies in the counterclockwise deviation zone and for bringing the limit sensor into a released condition as the rotary arm is out of the permissible angular extent; and an arm actuator operatively coupled to the rotary