A base station (2) is configured to receive, from a first wireless terminal (1), a first group identifier indicating a first terminal group, and allocate, to the first wireless terminal (1), a second radio resource, rather than a first radio resource, for device-to-device (D2D) communication performed by the first wireless terminal (1). The first radio resource is a radio resource which has already been allocated to any other wireless terminal which has sent the first group identifier. Meanwhile, the second radio resource is a radio resource which has already been allocated to any other wireless terminal which has sent a second group identifier indicating a second terminal group different from the first terminal group. It is thus, for example, possible to preventing a plurality of D2D communication signals, which are transmitted from multiple wireless terminals to a single wireless terminal, from being transmitted on the same radio resource.