To reduce processing delay by reducing an operation quantity in signal decoding.

A reception symbol and an output from a QR decomposing section 22 are supplied to a multiplying section 21, and the reception symbol is multiplied by the output from the QR decomposing section 22. A plurality of multiplying sections 21 and a plurality of QR decomposing sections 22 are provided depending on the number of sub-groups. The multiplying section 21 multiplies a conjugate transposed matrix by the reception symbol, thereby quadraturizing the reception symbol. A permutation channel matrix from an AGS section 23 is supplied to the QR decomposing section 22. A channel response matrix from a channel estimating section 14 is supplied to the AGS section 23. The reception symbols divided into a plurality of sub-groups from the multiplying section 21 and quadraturized are supplied to a local detector 24. The local detector 24 executes signal detection by hierarchical algorithm (e.g. M-algorithm) while utilizing each quadraturized sub-group.