A microwave-heating system irradiates sealed packaged foods with microwaves to heat the packaged foods at 100° C. or higher for heat sterilization. The microwave-heating system includes a microwave generator to irradiate the packaged foods with microwaves of 2450 MHz in a multi-mode and a microwave generator to irradiate the packaged foods in a waveguide with microwaves of 915 MHz in a single-mode.
