Provided is an ink jet printer including an electromagnetic wave generator that includes an electromagnetic wave generation section, a high-frequency voltage generation section, a transmission line, an ink jet head, and a control section. The electromagnetic wave generation section includes a first electrode, a second electrode, a first coil coupled to the first electrode or the second electrode in series, an impedance matching circuit constituted by a second coil and a capacitor coupled between the first coil and the high-frequency source. A thin ink film discharged from the ink jet head and attached to the recording medium is heated and dried by the electromagnetic wave generator. The control section controls a constant of the second coil or a constant of the capacitor of the impedance matching circuit according to information on the thin ink film.