We investigated the magnetoresistance and the Hall effect in an organic massless Dirac fermion system αあるふぁ-(BETS)₂I₃ under pressure. The Fermi energy of this system is slightly far away from the Dirac points, and thus the νにゅー = 1 quantum Hall state is realized in a low magnetic field at low temperatures. Moreover, the experimental formula for chemical potential as a function of temperature is clarified. We succeeded in detecting the inter-band effects of the magnetic field on the Hall conductivity when the chemical potential passes the Dirac points.