The oscillating circuit (100) includes a variable frequency oscillating circuit (10) for generating a clock signal (CK) whose frequency increases in response to an up-signal (UP) and decreases in response to a down-signal (DOWN), the frequency going up and down continuously between an upper-limit frequency and a lower-limit frequency. An up/down control circuit (20) outputs the down-signal when a duration of a low level of the clock signal drops below a first delay time and outputs the up-signal when the duration exceeds a second delay time longer than the first delay time.