A transmission device includes: a storage unit that holds test data used for checking occurrence/nonoccurrence of a communication abnormality; a serial conversion unit that converts image data to be transmitted and the test data stored in the storage unit into serial data; a transmission unit that transmits the serial data converted by the serial conversion unit to a reception device; and an initialization unit that, when an instruction of particular initialization is inputted, performs initialization on other circuits than the storage unit without performing initialization on the storage unit.