According to one embodiment, a tablet printing device 1 includes: a conveyer 10 configured to convey a tablet T; a laser displacement meter 30 configured to emit laser beams to the tablet T conveyed by the conveyer 10 and receive the laser beams reflected by the tablet T; a determination unit 81 configured to determine whether there is a split line on the upper surface of the tablet T conveyed by the conveyer 10 based on an output value of the laser displacement meter 30; and a printing unit 50 configured to perform printing on the tablet T conveyed by the conveyer 10 based on a determination result obtained by the determination unit 81.