To solve a problem that although the increase of the number of frequency blocks by allocating discontinuous subcarriers (RBs) as in OFDM enables an increase in multi-diversity effect and an improvement in throughput, the number of RB allocation patterns increases with the increase of the number of frequency blocks, resulting in an increase in the amount of information relating to the allocated RBs, the resource block allocation unit is determined when resource blocks discontinuous on the frequency axis are allocated to a terminal, and the number of bits of scheduling information indicating the allocated resource blocks by using Tree Based is set to the number of bits corresponding to the determined allocation unit.