An error correction decoder (101) counts the number of times of iterative decoding executed in the process of a predetermined error correcting operation, and outputs the iterative decoding count to an averaging circuit (102). The averaging circuit (102) calculates the average value of the iterative decoding counts input from the error correction decoder (101), and outputs the calculated average value of the iterative decoding counts to a comparator (103). The comparator (103) determines whether the iterative decoding count average value is larger than a predetermined threshold value. When determining that the average value is larger than the predetermined threshold value, the comparator (103) determines that a channel switching condition is met, and outputs a channel switching signal to a channel switching circuit (405). This makes it possible to output the channel switching signal under appropriate conditions without increasing the number of circuits in a wireless communication system using a highly coding gain code to be iteratively decoded.