  We investigate the Q-ball decay into the axino dark matter in the
gauge-mediated supersymmetry breaking. In our scenario, the Q ball decays
mainly into nucleons and partially into axinos to account respectively for the
baryon asymmetry and the dark matter of the universe. The Q ball decays well
before the big bang nucleosynthesis so that it is not affected by the decay. We
show the region of the parameters which realizes this scenario.
