The present invention provides a base station whereby efficient resource allocation for data signals is realized. In a base station (100) where a downlink control signal directed to a relay station is mapped onto an allocation area (R-PDCCH allocation area candidate) comprising M (where M is a natural number of 2 or greater) resource blocks, an allocation area candidate determination section (101) distributes the M resource blocks among N (where N is a natural number less than M) allocation area groups, and determines N resource block groups for the placement of the allocation area groups; and a control signal allocation section (102) maps the downlink control signal directed to the relay station onto the M resource blocks that are specified on the basis of the determined N resource block groups and the number of resource blocks constituting each of the allocation area groups.