To provide a DC motor controller which stably controls a traverse motor, even if the applied voltage of the traverse motor is not larger than the starting voltage.

The DC motor controller is provided with a determining means 341 for determining whether a traverse control signal S105 for controlling the traverse motor 15 has reached a reference value which is set to a value higher than starting voltage of the traverse motor 15; a control pulse generating means 342 which PWM-modulates the traverse control signal S105, with the ratio of a value of the traverse control signal S105 and the reference value as the duty ratio and generates a control pulse signal S108 having amplitude higher than the reference value; an amplifying means 343 for amplifying the traverse control signal S105 and generating an amplification signal S109; and a selecting means 344 for selecting the control pulse signal S108, when the traverse control signal S105 is not larger than the reference value and the amplification signal S109, when the signal exceeds the reference value and outputting it as a control signal for controlling the traverse motor 15.