An MIMO receiver and MIMO communication system which can have a small hardware scale even if the number of antennas used for MIMO communication. In a radio communication device (200), a receiving section (220) receives a spatially multiplexed signal generated by mutually-different and spatially multiplexing transmission signals, a first signal demultiplexing section (230) subjects a linear operation to the received spatial multiplexed signal to demultiplex the spatial multiplexed signal, and a second signal demultiplexing section (240) demultiplexer the demultiplexed spatially multiplexed signal into the transmission signals. When the received signal is demultiplexed by a single demultiplexing, as the number of multiplexed spatial multiplexed signal increases, the demultiplexer becomes complicated, and the hardware scale increases. When the received signal is demultiplexed by a plurality of demultiplexings, the hardware scale is relatively small.