In a synchronization system, a frequency divider circuit generates a divided clock by dividing a reference clock in a first division ratio. First and second devices operate in synchronization with the reference clock and the divided clock. A division ratio detection circuit, for each period of the divided clock, detects a division ratio of the divided clock based on a count value counted in synchronization with the reference clock and output the division ratio as a second division ratio. A decoder generates a strobe signal, which is for controlling a timing at which the first device transmits and receives a signal to and from the second device, based on the count value and the second division ratio. The first device communicates with the second device through a bus, which operates in synchronization with the divided clock, based on the strobe signal.