An irradiation system comprises a beam generation source, a mass analysis device, a beam transformer, a deflector for scanning which swings the beam reciprocally, a beam parallelizing device, an acceleration/deceleration device, and an energy filtering device. According to this invention, a hybrid angular energy filter generating both electric and magnetic fields to bend trajectories is provided as the energy filtering device. A pair of multi-surface energy slit units each having a plurality of energy slits that are switchable therebetween depending on an ion species for irradiation are further provided on a downstream side of the hybrid angular energy filter. It is possible to selectively irradiate a target wafer with high-current beams from low energy to high energy in the conditions where contamination such as neutral particles, different kinds of dopants, ions with different energies, metal, and dust particles is extremely small in amount.