We report the effects of a magnetic field on a pressure-induced valence transition in EuRh2Si2by using magnetization measurements under high pressure. The M-H curves at 2 K under variouspressures up to 1.18 GPa exhibit no anomalies associated with a field-induced valence transition. Onthe other hand, the M-H curves under a pressure of 1 GPa, where a temperature-induced valencetransition occurs at around 30 K, show a clear metamagnetic transition with a large hysteresis ataround 30 K. This behavior corresponds to a field-induced valence transition. The M-T curvesin magnetic fields indicate that with increasing magnetic field, the temperature-induced valencetransition shifts toward lower temperature and that its thermal hysteresis becomes larger. Coolingthe sample under a pressure of 1 GPa in a magnetic field of 7 T collapses the valence transitionand stabilizes the magnetic high-temperature phase down to 2 K. Besides, with decreasing magneticfield, three sharp valence transitions toward the nonmagnetic Eu3+ direction are observed: 4.65,2.65 and 1.93 T.