A codebook creating method involves acquiring amplitude or power of channel state information of channels between the transmission antennas and the reception antenna, mapping elements of a codeword of an initial codebook dynamically to the respective transmission antennas based on the amplitude or power of the channel state information thereby to create a first codebook, and scaling norms of elements corresponding to the respective transmission antennas in a codeword of the first codebook by using norm scale factors of the respective transmission antennas fixed based on the amplitude or power of the channel state information. An initial codebook creating method involves configuring a predetermined element of the codeword of the initial codebook to have a predetermined phase resolution, and configuring other elements of the codeword of the initial codebook to be arranged in an increasing or decreasing order of phase resolution.