A load controller includes: a first input circuit which detects that a drive instruction signal by an operation of a drive instructing unit is less or equal to a first input threshold value; a first constant current source activated in accordance with the detection; a PWM signal supply unit that is activated by the first constant current source and supplies a PWM signal having a prescribed frequency and a duty ratio; a constant control signal supply unit that supplies a constant control signal during failure of the first input circuit or the first constant current source; a drive control unit that generates a PWM drive control signal in accordance with the PWM signal and generates a constant drive control signal in accordance with the constant control signal; and a load driving element that is controlled by the PWM drive or constant drive control signal to drive a load.