The invention relates to a radio receiver which receives reception waves modulated with a frame being a sequence of slots and reproduces transmission information that is distributed to the slots. An object of the invention is to increase the reliability of channel inference and improve the transmission quality without substantially altering a basic configuration. A radio receiver of the invention performs quasi-synchronous detection on reception waves modulated with a frame; determines an error in a sequence of first vectors and a sequence of second vectors as an average of deviations of particular symbol positions to be indicated by the sequence of first vectors indicating a sequence of words included in each slot in a signal space, and the sequence of second vectors indicating known information included in the slots; and compensates for the error in the signal space.