To provide an improved microwave heating apparatus capable of providing sufficient heating processing quantity with even and efficient microwave heating.

More efficient and more heating processes can be executed in a short period of time by using a first heating furnace 1 for rising temperature of an object to be heated to a predetermined process temperature, a second heating furnace 2 for keeping the object to be heated at the predetermined process temperature. The heating device is equipped with a transporting means 3 for making a sheet-like object W to be heated to sequentially pass through in heating furnaces 1, 2. In the first heating furnace 1, microwave is introduced from a waveguide 6 to a microwave resonating cavity 4 and an even electric field in z direction is generated inside. To radiate microwave introduced into the resonating cavity 4 to the object W to be heated, the object W is moved through an inlet 7a and an outlet 8a in x direction. The object W is rapidly heated in a short period of time in the heating furnace 1 and reaches the predetermined process temperature and can promote increase of heating processing quantity.