To provide a printing device which can precisely print image data to an object to be printed, even in case the conveyance velocity of an auxiliary conveyance member varies and a code detection interval is short.

The printing device comprises a printing head 11 for printing image data line by line, a retaining part 41 for retaining one piece of card-like object to be printed C, an auxiliary conveyance member 4 having a plurality of codes juxtaposed in a conveyance direction, conveyance means 13 and 14 which carry the auxiliary conveyance member 4 to printing heads 11 at a specified feed velocity, and a code detection means 17 for detecting the code. In addition, the device performs a sequential printing control of the printing heads 11 corresponding to the respective lines for the image data in synchronization with the detection of the code by the code detection means 17 and suspends the printing control, in case a following code is detected in the process of controlling the printing operation of the printing head 11 corresponding to an optional line, and performs the printing control corresponding to the following line.