1. A terminal apparatus comprising:a receiver that monitors an enhanced physical downlink control channel (ePDCCH), wherein
resources in a resource block pair within the ePDCCH each constitute constituting a second element, the resources being obtained by dividing at least a part of the resource block pair by N (N is a natural number),
the ePDCCH is received using one or more first elements, and
each of the one or more first elements includes a plurality of the second elements; and
a controller that selectively uses either a first value or a second value as the number of the second elements in each first element, wherein
the resource block pair is made up of two PRBs (physical resource blocks) that are contiguous in a time domain in a downlink,
which one of the first value and the second value is to be used depends on at least a Radio Resource Control (RRC) signal transmitted from a base station apparatus, and
the RRC signal is used to determine available resources for downlink transmissions.