The transmitter section has a coder for converting an image signal into the coded data and producing the coded data at its output, a timer for producing time information which indicates a time lapse from a reference time, a first time data adding unit for adding the time information from the timer as the first time data to the coded data from the coder, a transmitter-side buffer for writing and reading the coded data with the first time data added, and a second time data adding unit for adding the time information from the timer as the second time data to the coded data read from the transmitter-side buffer, and sending the coded data to the transmission path. The receiver section has a unit for detecting the second time data from the coded data which is transmitted through the transmission path, a receiver-side buffer for writing and reading the coded data transmitted through the transmission path, a unit for detecting the first time data from the coded data read from the receiver-side buffer, a unit for detecting a total time delay of the coded data in the transmitter and receiver section on the basis of the detected first and second time data, and a unit for controlling the phase of the coded data read from the receiver-side buffer in response to the total delay time of the coded data detected by the detecting means.