A directional pattern table memory stores combined directional pattern groups in each of which combined directional patterns are ordered by different predetermined priority according to a different radio propagation environment. A controller computes a communication performance expected value based on RSSIs for when an initial combined directional pattern is set on steerable antenna apparatuses; selects one combined directional pattern group based on relative strengths of RSSIs; and according to the priority, sequentially sets combined directional patterns of the selected one combined directional pattern group, on the steerable antenna apparatuses, computes a communication performance value based on a PHY rate and a PER at each of sequential settings, and performs communication using a combined directional pattern with a communication performance value that first exceeds the communication performance expected value.