A laser-driven particle beam irradiation apparatus includes: a particle beam generator irradiating a target with pulsed laser light to emit a laser-driven particle ray a beam converging unit forming a transportation path which guides the emitted laser-driven particle ray to an object and spatially converging the laser-driven particle ray an energy selector selecting an energy and an energy width of the laser-driven particle ray an irradiation port causing the laser-driven particle ray to scan the object to adjust an irradiation position in the object and an irradiation controller controlling operation of the particle beam generator, the beam converging unit, the energy selector and the irradiation port. The beam converging unit generates a magnetic field on a trajectory of the laser-driven particle ray and converging the laser-driven particle ray by the magnetic field, the magnetic field forcing divergence components of the laser-driven particle ray that go away from a center of the trajectory back to the center of the trajectory.
