SWITCH DEVICE

PROBLEM TO BE SOLVED: To reduce fluctuations in voltage caused at an input/output terminal when a control signal rises and falls.SOLUTION: A switch device includes: an analog switch circuit 3 having a pair of input/output terminals 11, 12, a control terminal 13 fed with a control signal S2, a main switch 16 comprising MOS transistors, and a control circuit 19; a voltage generation circuit 4 for generating a reference voltage Vr at a set voltage to be output from a voltage output terminal 4a; and a make/break circuit 5 disposed between the input/output terminal 12 of the analog switch circuit 3 and the voltage output terminal 4a to switch on/off the output of the reference voltage Vr to the input/output terminal 12. The analog switch circuit 3 is transitioned from either of an on state and an off state to the other while the make/break circuit 5 turned on outputs the reference voltage Vr to the input/output terminal 12.