A high-frequency heating apparatus comprises a semiconductor power converter (33) which is supplied with electric power from a commercial power supply, etc., a radio wave radiation section (32) which is energized by the semiconductor power converter (33), a control section (34) which controls the operation of a semiconductor element (28) of the semiconductor power converter (33), and a start control section (41) which controls the operation of the control section (34) at the start time of the high-frequency heating apparatus. The start control section (41) controls the operation of the control section (34) so that the radio wave output power from the radio wave radiation section (32) at the start time of the high-frequency heating apparatus becomes greater than that in the steady operation state thereof, whereby the optimization of the performance and price of the heating apparatus can be realized.