The present invention relates to a radio receiver or a diversity receiver where reception waves respectively reaching a plurality N of branches in parallel are cyclically selected at a first frequency equal to a value of the product of a symbol frequency, the plurality N being a total number of branches, and a prescribed number E equal to or greater than “2”, the instantaneous values of selected reception waves are sequentially sampled at a second frequency equal to or higher than the first frequency, and a resulting sequence of instantaneous values is cyclically split at the first frequency, whereby sequences of instantaneous values individually corresponding to the plurality N of reception waves are output. In a radio transmission system applying the above radio receiver or diversity receiver, reception waves reaching a plurality of branches are received in parallel without largely increasing hardware in scale.