In a system for performing clock generation for each semiconductor device, synchronization between the semiconductor devices is achieved without causing a count value in a counter to be discontinuously changed. A semiconductor device 1 includes a clock oscillator 2, a counter 3 configured to count the number of clocks, a periodic register 4 in which a value corresponding to a period for synchronization is set, a comparison circuit 5 configured to compare the count value in the counter 3 with the set value in the periodic register 4, a match flag register 6 in which a predetermined value is set when the count value coincides with the set value, a match output terminal 7 configured to output the value in the match flag register 6 from the own semiconductor device, a match input terminal 8 to which a value output from another semiconductor device to be synchronized is input, and a reset circuit configured to reset the counter 3 and the match flag register 6 when both the value in the match flag register 6 of the own semiconductor device and the value input to the match input terminal 8 become a predetermined value.