A multibeam radar system includes a multibeam radar module having n (n is a natural number of at least 3) transmitting/receiving channels for transmitting high-frequency signals and receiving echo signals, and a radar circuit for detecting a distance up to an object which produces the echo signals and/or a relative speed of the object from a relationship between the high-frequency signals and the echo signals in the transmitting/receiving channels. The radar circuit includes a channel controller for selecting sets of m (m is a natural number smaller than n) adjacent transmitting/receiving channels sequentially to transmit the high-frequency signals and receive the echo signals in a high-azimuth-resolution mode. The channel controller may also select the transmitting/receiving channels sequentially one by one to transmit the high-frequency signals and receive the echo signals in a low-azimuth-resolution mode.