A high-frequency control unit includes an integration value calculator calculating a measured integration value, which is a measured value of an integration value of an output high-frequency electric power from an output start time, with a passage of time. The high-frequency control unit includes a target locus setting section setting target locus which indicates, with a passage of time, a target integration value that is a target value of the integration value of the output high-frequency electric power from the output start time, and a controller comparing, with a passage of time, the measured integration value with the target locus, and controlling, with a passage of time, an output state of the high-frequency electric power based on a comparison result.