Abstract: In this control circuit for a DC motor, there are provided: a device which generates a triangular voltage wave; a device which generates a variable reference voltage; a device which compares the voltage from the triangular voltage wave generator and the voltage from the variable reference voltage generator, and produces a speed variation control output according to the result of this comparison; and a device which controls the supply of electric current to the DC motor according to the thus produced speed variation control output. Optionally, control power source lines from the device for controlling the supply of electric current to the DC motor are connected to the two ends of an armature of the DC motor. By this simple construction the number of parts of the control circuit is minimized, and the construction is made compact, light, and cheap.