A CR oscillator has a first logic inversion unit including odd-number stages of logic inversion elements connected in series, a second logic inversion unit including odd-number stages of logic inversion elements connected in series, the second logic inversion unit being connected to a latter stage of the first logic inversion unit, and two or more resistors and a capacitor connected in series between an output node of the first logic inversion unit and an output node of the second logic inversion unit. An electric potential in accordance with an electric potential of an intermediate node between the two or more resistors is supplied to an input node of the first logic inversion unit.