Abstract: The present invention addresses the problem of providing a heating furnace that sufficiently exhibits the microwave effect produced by microwave heating and allows economical heating taking advantage of the characteristics of each heating method. The provided microwave composite heating furnace (1) is equipped with: a housing (10); a heating container (11) for accommodating and heating an object to be heated; a heating means (12) for heating the heating container (11) from the outside; a microwave irradiation device (13); a to-be-heated object supplying device (14) that supplies the object to be heated to the inside of the heating container (11); a gas introducing means (15) for introducing gas into the heating container (11); and a gas recovery means (16) for recovering the gas generated when heating the object to be heated.