In order to radiate microwaves from a waveguide tube to a whole area from end to end of a radiation area within a heating chamber, and to heat uniformly an object to be heated without using a driving mechanism, a microwave heating device of the present invention includes openings for radiating the microwave from the waveguide tube to the inside of the heating chamber. When the load voltage does not exceed a first voltage, the two-terminal current controller operates in a first mode for conducting a second current associated a rectified AC voltage, thereby limiting the first current to zero and adjusting the second current accordingly. The push-pull mechanism includes a handle and a lock element.