A radio communication apparatus includes a radio frequency unit that receives signals transmitted from a transmitter, and a baseband processor that obtains channel estimates based on the received signals and performs signal detection based on the channel estimates according to a QRM-MLD method. The baseband processor includes a stream separator that, in a first stage, detects a region to which a signal belongs, selects symbol candidates based on the detected region, and calculates metrics for the selected symbol candidates. In a second stage, the stream separator selects symbol candidates based on the metrics calculated for the symbol candidates selected in the first stage. After starting calculation of the metrics for the symbol candidates selected in a previous stage, the stream separator selects symbol candidates of a next stage based on metrics of surviving paths to which the symbol candidates whose metrics have been calculated belong.