Provides a normalizing apparatus that normalizes input signals to a turbo decoder without significantly increasing a size of a circuit. An input signal buffer (341) obtains a sum S for N pieces of input signal data I(i). An input data averaging part (342) obtains an average A by dividing the sum S by the number of data N. A divider (343) obtains normalized data I(i)/A by dividing the input signals I(i) by the average A. A weighting part (345) multiplies the normalized data I(i)/A with a weighting coefficient .alpha., which is determined based on a ratio of a number of input data and a number of output data in rate matching. As a result, the normalization is made possible. Because a signal receiving quality does not need to be determined, an increase in circuit size is inhibited.