A radio receiver disclosed is composed of a signal processing part, which includes a receive band pass filter 2 and a receive low noise amplifier 3, to process receive signal and discharge gas with time, the signal processing part being cooled by the cooling means 6, wherein the radio receiver is provided with an airtight container 10 that operates as inner sealing means to seal the receive band pass filter 2 and the receive low noise amplifier 3 to retain the gas, and a vacuum container 5 that operates as outer sealing means to seal in vacuum the airtight container 10 such that an interspace 12 between that and the airtight container 10 forms a vacuum insulating space to insulate in vacuum the airtight container 10 from outside.