A wireless relay station apparatus for enabling a mobile station and a base station to reliably receive network coding data and to provide sufficient reception performance is provided. (1) A repeater divides data X received from a mobile station into important data and non-important data and divides data Y received from eNB into important data and non-important data. Next, (2) the repeater places the data so that important data Sx for the mobile station and important data Sy for the eNB do not overlap, XORs (exclusive ORs) them, and generates network coding data X (X) Y. (3) The repeater applies downlink propagation inverse characteristic H1 -1 to important data portion Px (X) Sy for the mobile station and on the other hand, applies uplink propagation inverse characteristic H0 -1 to important data portion Sx (X) Py for the eNB in the network coding data X (X) Y for transmission.