A calibration system for performing calibration in a drawing device, the drawing device comprising at least one exposure head configured to emit a beam for exposure toward an exposure surface of a substrate, the substrate having a long-sheet shape and being conveyed in a longitudinal direction by being supported on part of an outer periphery of a conveying drum having a cylindrical shape, comprising: an optical system that is provided insertably into and removably from an optical path of the beam that is emitted from the exposure head and enters the exposure surface, the optical system configured to guide at least part of the beam in a direction different from that of the optical path when the optical system is inserted into the optical path; a movement mechanism configured to insert and remove the optical system into and from the optical path; and an optical sensor having a light-receiving surface for receiving at least part of the beam that is guided by the optical system when the optical system is inserted into the optical path, the optical sensor being configured to output a detection signal by detecting an irradiation position and an irradiation intensity at the light-receiving surface of at least part of the beam that has entered the light-receiving surface, characterized by the position of the optical sensor being fixed, and the calibration system further comprising: a second optical system configured to guide at least part of the beam, guided by the optical system in a direction different from that of the optical path, in a direction toward the light-receiving surface of the optical sensor; and a third optical system configured to allow at least part of the beam guided by the second optical system to be imaged on the light-receiving surface. an optical system that is provided insertably into and removably from an optical path of the beam that is emitted from the exposure head and enters the exposure surface, the optical system configured to guide at least part of the beam in a direction different from that of the optical path when the optical system is inserted into the optical path; a movement mechanism configured to insert and remove the optical system into and from the optical path; and an optical sensor having a light-receiving surface for receiving at least part of the beam that is guided by the optical system when the optical system is inserted into the optical path, the optical sensor being configured to output a detection signal by detecting an irradiation position and an irradiation intensity at the light-receiving surface of at least part of the beam that has entered the light-receiving surface, characterized by the position of the optical sensor being fixed, and the calibration system further comprising: a second optical system configured to guide at least part of the beam, guided by the optical system in a direction different from that of the optical path, in a direction toward the light-receiving surface of the optical sensor; and a third optical system configured to allow at least part of the beam guided by the second optical system to be imaged on the light-receiving surface. a second optical system configured to guide at least part of the beam, guided by the optical system in a direction different from that of the optical path, in a direction toward the light-receiving surface of the optical sensor; and a third optical system configured to allow at least part of the beam guided by the second optical system to be imaged on the light-receiving surface.