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.