The present invention relates to a scheduling apparatus of a base station supporting Automatic Repeat reQuest (ARQ) method. In particular, the present invention discloses scheduling a data unit transmitted to a mobile station from a base station providing ARQ method for correcting an error in wireless data communication and generating a high rate frame.According to the present invention, there is provided a transmission controlling apparatus comprising a receiver to receive mobile station status information from a mobile station connected with a base station, a schedule managing unit to determine transmission priority of a plurality of data units to be transmitted to the mobile station based on the received mobile station status information, and a transmitter to transmit the data units to the mobile station based on the determined transmission priority.