An infrared detecting device for reducing current consumption while maintaining performance is disclosed. The device includes a drive power supply circuit which comprises a current generating circuit and a distribution circuit, and which supplies a drive current to each of signal circuits comprising an I/V conversion circuit, a voltage amplification circuit, a detection circuit and an output circuit. The current generating circuit includes a reference current source, a fixed current source providing a fixed current based on the reference current and a variable current source providing a variable current stepped up or down to any different currents based on the reference current. The distribution circuit distributes the drive current to a part of the signal circuits based on the current from the fixed current source and distributes the drive current to a remaining part of the signal circuits based on the current from the variable current source.