PURPOSE: To obtain the semiconductor integrated circuit consisting of a prescaler which has a large delay margin at the time of frequency dividing operation switching.

CONSTITUTION: This semiconductor integrated circuit is equipped with a 1st frequency dividing circuit 31 which consists of D type flip-flops 4 and 5, and 6, divides the frequency of an input signal by 5 or 6 according to the output of a control circuit 33, and outputs the result and a 2nd frequency dividing circuit 32 which inputs the output of the D type flip-flop 5 in the stage right before the final stage of the 1st frequency dividing circuit 31 at its clock terminal and outputs an output signal 10 obtained by 10 or 11 frequency division.