To provide a DLL circuit including: a first phase determination circuit that compares phases of rising edges of an external clock and a first internal clock; a second phase determination circuit that compares phases of falling edges of the external clock and the first internal clock; an adjusting unit that adjusts positions of active edges of internal clocks based on determination results; and a control circuit that sets one of adjustment amounts of the second and third internal clocks to a larger value than the other, in response to a fact that adjustment directions of the active edges of the second and third internal clocks are mutually the same. With this arrangement, a duty can be set nearer to 50% while performing phase adjustment. Accordingly, the time required to lock the DLL circuit can be shortened.