The current drive device of the present invention includes: a current source transistor for allowing a preset drive current to flow to a drain; a cascode transistor cascode-connected to the current source transistor; a switch circuit for switching ON/OFF flow of the drive current through the drain of the cascode transistor and a circuit to be driven; and a bypass circuit for allowing the drive current to flow therethrough to bypass the switch circuit and the circuit to be driven when the switch circuit is OFF.