A microwave treatment device of the present disclosure includes heating chamber (1) for accommodating object (2) to be heated, microwave generator (3), heater (7), power feeder (4), detector (5), and controller (6). Microwave generator (3) generates microwaves. Heater (7) includes a heat source other than the microwaves and heats an inside of heating chamber (1). Power feeder (4) supplies the heating chamber with the microwaves. Detector (5) detects reflected power from power feeder (4). Controller (6) controls heater (7) and microwave generator (3). When heater (7) carries out heating, Controller (6) causes microwave generator (3) to generate the microwaves in heating by heater (7). The microwaves have output power such that the reflected power at a level detectable by detector (5) returns. By present disclosure, by understanding progress of cooking, a heating target can be appropriately cooked.