A transmitting device has a transmission data generating part and an output buffer part. The transmission data generating part transmits a data and a clock, which are to be transmitted to a receiving device, and outputs them to the output buffer part. The output buffer part includes a data transmitting part and a clock transmitting part. The clock transmitting part generates and transmits a clock intermittently phase-shifted. The data transmitting part transmits the data in sync with the clock transmitted from the clock transmitting part.