This current detection device is configured from: an annular magnetic material core that forms a closed magnetic path around a pair of conducting wires in which conduction currents flow; an excitation coil wound on the magnetic material core; an oscillation circuit unit that applies a rectangular wave output voltage to the excitation coil; a power supply unit that supplies power to an operation amplifier that generates the rectangular wave output voltage in the oscillation circuit unit; and a difference current calculation unit, which detects a power supply current flowing from the power supply unit to the operation amplifier, and which calculates a difference current between the conduction currents flowing in the pair of conducting wires. Consequently, excellent noise resistance is achieved, and the configuration of the current detection device is simplified.