A decoding apparatus includes a radio section, TFCI decoding characteristic feedback section, and dedicated physical data channel correcting section. The radio section receives data on a dedicated physical control channel and data on a dedicated physical data channel, which are coded into a complex code of a single system which is to be transmitted as an uplink signal from a mobile unit to a base station in a 3rd generation cell phone system. The TFCI decoding characteristic feedback section determines the TFCI decoding characteristics of a coded TFCI code on the dedicated physical control channel. The dedicated physical data channel correcting section performs data correction for the dedicated physical data channel on the basis of a determination result on the TFCI decoding characteristics. A decoding method and radio base station apparatus are also disclosed.