An ink jet printer is provided with an ink jet head, a sub ink tank, a carriage, a main body, and an ink supply device. The ink jet head includes an ink passage and a nozzle communicated with the ink passage. The sub ink tank is communicated with the ink passage of the ink jet head. The sub ink tank is elastically deformable. The ink jet head and the sub ink tank are mounted on the carriage. The carriage is capable of moving. The main body houses the ink jet head, the sub ink tank, and the carriage. The main body has a space for housing a main ink tank that is to be communicated with the sub ink tank. The ink supply device supplies ink within the main ink tank to the sub ink tank by applying a pushing force to the sub ink tank and releasing the pushing force after applying the pushing force.