A transmission apparatus for transmitting packets through a plurality of transmission channels includes: an identifying unit configured to identify, as a candidate, one or more sets each including one or more transmission channels for use in transmitting a plurality of transmission target data packets, based on transmission speed of the plurality of transmission channels; and a determining unit configured to determine, among the one or more sets identified as the candidate by the identifying unit, a set including less number of transmission channels than another set, as a set of the transmission channel for use in transmitting the transmission target data packets.