PURPOSE: To simply constitute the titled oscillation circuit by providing plural constant current sources and switch circuits arranged between the said plural constant current source and capacitor and using the switch circuit so as to change number of the constant current source connected to the capacitor thereby varying the frequency of an oscillated signal stepwise.

CONSTITUTION: The oscillated frequency depends on the quantity 1' of the charge/discharge current of the capacitor 1. Then the oscillated frequency depends on the number of the constant current sources connected to the capacitor 1. Thus, the oscillated frequency varies stepwise with the number of the constant current sources connected to the capacitor 1 by the switch circuits 6, 9, 11, 14, 15, 18. Thus, when the required oscillated frequency is decided corresponding to the number of the current source, for example, the oscillated frequency reaches the required oscillated frequency accurately without any adjustment by using the switch circuits 6, 9, 11, 14, 15, 18 to connect the required number of the constant current sources to the capacitor 1.