To provide a circuit which obtains a stable frequency or a delay element when a reference frequency is obtained.

A switchover device 5 alternately selects, in chronologic order, a first oscillation circuit 6 composed of a first impedance circuit 1 with a first temperature variation rate and a first active circuit 3, and a second oscillation circuit 7 composed of a second impedance circuit 2 with a second temperature variation rate with an opposite variation direction to that of the first temperature variation rate and a second active circuit 4. When an absolute value of a temperature coefficient of the first impedance circuit 1 is larger than a temperature coefficient of the second impedance circuit 2, an operating time of the first oscillation circuit 6 is reduced, and the rate of the operation time of the oscillation circuit is set with a rate opposite to that of the temperature coefficient so that the operating time of the second oscillation circuit 7 whose temperature coefficient is small, operates long. Since two temperature coefficients exist whose temperature variation directions are opposite, temperature variation as an average is almost removed or extremely reduced. An oscillation frequency is obtained in which the temperature variation is quite small as a time average and the temperature variation rate is improved.