A three-dimensional printing device includes a first head having a first nozzle array that ejects liquid, a second head having a second nozzle array that ejects liquid, and a moving mechanism having a linear motion mechanism that changes relative positions of the heads with respect to a three-dimensional workpiece. The first region of the workpiece is more inclined with respect to the first axis than the second region of the workpiece. A time period when the first nozzle array faces the first region and the second nozzle array faces the second region is a first time period. In the first time period, the first nozzle array ejects the liquid onto the first region in a first ejection cycle. In the first time period, the second nozzle array ejects the liquid onto the second region in a second ejection cycle. The first ejection cycle is shorter than the second ejection cycle.