A DLL circuit includes a delay line that generates an internal clock signal by delaying an external clock signal CLK, a counter circuit that sets a delay amount of the delay line, a phase detecting circuit that generates a phase determination signal based on a phase of the external clock signal, and an antialiasing circuit that prohibits the counter circuit to update a count value based on the phase determination signal, in response to a fact that a jitter component included in the external clock signal is equal to or higher than a predetermined frequency. With this configuration, a problem that the internal clock signal is continuously controlled to a wrong direction due to malfunction of aliasing does not occur.