Orthogonal converters perform orthogonal conversion on the N time-series data extracted from a received radio signal. Multi-user detectors extract transmitted signals from respective transmission devices, from the time-series data which has been subjected to the orthogonal conversion. Inverse orthogonal converters perform inverse orthogonal conversion on the extracted transmitted signal. Rectangular filter circuits remove Mh time-series data at the front end and Mt time-series data at the rear end, from the transmitted signal which has been subjected to the inverse orthogonal conversion, so as to extract Nw time-series data. Deinterleaver circuits deinterleave the aforementioned time-series data. Decoders decode the time-series data for output.