Provided is a microwave heating device, comprising a heating chamber which carries a to-be-heated object and heats based on microwaves, a microwave supply portion for supplying the microwaves and a waveguide tube structure for transmitting microwaves from the microwave supply portion to the heating chamber. The waveguide tube structure has a first waveguide tube connected to the microwave supply portion, a second waveguide tube that couples the microwaves from the microwave supply portion and being transmitted in the first waveguide tube through a coupling shaft and is provided with a microwave radiation opening that opens in a manner of irradiating the coupled microwaves. Therefore, the to-be-heated objected can be heated by the microwaves more uniformly.