PURPOSE: To improve the timing accuracy of picture dot processing, by detecting the temperature around a scan-driving device, and applying a power corresponding to the detected temperature to the exciting coil of a pulse motor for scanning drive.

CONSTITUTION: A microcomputer 4 applies a step pulse signal (c), a direction instructing signal (a) and a reset signal (b) to a phase excitation distributing circuit in a timing in response to the print request externally. A motor driving current control circuit is provided with a thermister RT having a negative temperature coefficient detecting the ambient temperature, and the thermister RT changes the exciting current applied to a pulse motor 1 depending on the temperature, the torque of the pulse motor 1 is compensated for temperature, allowing to avoid the difference between the step pulse signal (c) and the motor rotating position from being changed due to the ambient temperature change.