According to one embodiment, a tablet printing device (S) includes: a first conveyor (1) conveying a tablet while holding a other surface of the tablet； a second conveyor (2) conveying the tablet transferred from the first conveyor (1) while holding a one surface of the tablet； a first print head (31) performing printing on the one surface of the tablet； a second print head (41) performing printing on the other surface of the tablet； a first detection mechanism (32) detecting the one surface of the tablet； a second detection mechanism (33) detecting the other surface of the tablet； and a controller (5) sending a printing instruction to the first and the second print heads (31, 41) based on information related to the state of a split line included in detection information on the one surface of the tablet or detection information on the other surface of the tablet.
