A disclosed base station apparatus includes: a TTI-length determining unit which determines, based on downlink receive quality information transmitted from a mobile station, whether data is to be transmitted in a first TTI with, as a unit, a predetermined period no shorter than a subframe length, or in a second TTI with, as a unit, a period shorter than the first TTI; a number-of-subframes determining unit which determines a number of subframes making up the determined TTI; a reporting unit which reports the determined TTI and the number of subframes making up the determined TTI to the mobile station; and a scheduler which performs scheduling based on the determined TTI and the number of subframes making up the determined TTI.