A medical charged particle irradiation apparatus capable of irradiation from upward and horizontal directions and performing a preparing/ascertaining work without any separate device such as a moving capsule or the like comprising a patient's bed, on which a patient lies, a transport equipment for injecting and transporting charged particle beams toward the patient's bed, an irradiation field forming device for forming an irradiation field for the beams transported by the transport equipment, and a gantry provided to be rotatable about an axis of rotation, and wherein the irradiation field forming device is eccentrically arranged such that an axis of irradiation passes a position different from the axis of rotation, and the patient's bed is arranged on an opposite side of the transport equipment to a plane, which contains the axis of rotation and is substantially perpendicular to the axis of irradiation.