When a determination is made that communication by an SM scheme is suitable, a setting unit performs switching from a communication level by an STC scheme to the communication level by the SM scheme, between the communication level at a first level of MCS by the space-time coding scheme and the communication level at a second level of MCS by the SM scheme. When a determination is made that communication by the SM scheme is unsuitable, the setting unit performs switching from the communication level by the STC scheme to the communication level by the spatial multiplexing scheme, between the communication level at a third level of MCS, which is higher than the first level, by the space-time coding scheme and a fourth level of the modulation scheme and the coding rate, which is higher than the second level, by the SM scheme.