A sample and hold circuit that is provided with an input stage amplifier circuit for amplifying an input signal and a hold circuit for holding an output signal of the input stage amplifier circuit, with a sampling clock signal as a trigger, is further provided with a hold circuit bias current switching circuit for switching a bias current of the hold circuit to a first separate circuit that is functionally independent of the sample and hold circuit, in a case where the hold circuit is in a hold period, to supply the bias current to the circuit.