A communication apparatus has an upper-layer evaluation parameter acquisition part configured to acquire an evaluation parameter for an upper-side layer among a plurality of layers included in a network, a fragment-size decision part configured to decide a fragment size to be used in dividing a packet that includes information of an upper-side layer into fragments, based on the evaluation parameter acquired by the upper-layer evaluation parameter acquisition part, and a fragment controller configured to divide the packet into a plurality of fragments based on the fragment size.