A mobile station capable of reducing the probability of collision of RACH data in a random access. In this mobile station, a moving speed determining part (106) determines a moving speed of the mobile station (100). A frame selecting part (105) selects, based on both an arrangement pattern indicated by arrangement pattern information and the moving speed, one of frames to be used for transmission of RACH data. In accordance with a result of the selection, the frame selecting part (105) outputs the number of symbols per block to a block dividing part (113), and also outputs the number of duplications of each of blocks to a duplicating part (114). The block dividing part (113) divides the RACH data symbols, which are sequentially received from a modulating part (112), into blocks in accordance with the number of symbols per block received from the frame selecting part (105), thereby generating RACH data blocks. The duplicating part (114) duplicates the RACH data blocks in accordance with the number of duplications received from the frame selecting part (105).