A oscillation circuit has a delay loop with a clock delay circuit for generating a delayed clock signal. The clock delay circuit has a selector and has multiple delay elements with delay times differing from each other. The clock delay circuit may produce a time lag which is less than the delay time of any single delay element, the time lag being based on the difference between the time delays of different delay elements. A phase comparator compares the phase of a signal associated the delay loop to that of a reference clock signal, generating a phase difference clock signal. A delay setting circuit can cause the selector to change the selection of one delayed clock signal according to the phase difference signal from the phase comparator in such a manner as to reduce the phase difference.