To provide a high-frequency cooking apparatus of which installation performance, handling performance, and quality can be enhanced. A high-frequency cooking apparatus 10 for heat-processing an object to be heated, by supplying high frequency and steam into a heating chamber, is provided with a water tank 13 which stores water for generating the steam. The water tank 13 is detachably assembled toward the front to a lower part of a body 11 of the high-frequency cooking apparatus which has the heating chamber, and a tray 12 is integrally assembled to the water tank 13.