A receiver directs the center of the main beam of the antenna directivity response in a desired direction by passing signals received by n antenna elements 1a to 1d through a phase shifter 3. An output from the phase shifter 3 is passed through a receiving filter 5 and is then amplified by a low noise amplifier 6 to be delivered as an output. The phase shifter 3 is confined together with the receiving filter 5 and the amplifier 6 in a cryostat 8, and the phase shifter 3 as well as the receiving filter 5 and the amplifier 6 are cooled down by cooling means 9 through a cold stage 9a, whereby the thermal noises generated therein are reduced to a minimum.