A load driving device controls two motors by PWM signals. When a standard duty ratio of the PWM signals is 50% and a level of a drive instruction is the standard duty ratio, the standard duty ratio are output to the respective motors to provide a reverse phase relationship that the PWM signal of the standard duty ratio does not overlap. A continuous off-period and the standard PWM signal output when the level of the drive instruction is lower than the standard, and the continuous on-period and the standard PWM signal output when the level of the drive instruction is higher than the standard are changed over at the ratios corresponding to the level of the drive instruction.