According to embodiment, an x-ray computed tomography apparatus includes a gantry apparatus. The gantry apparatus includes a housing, at least one light projector, and a transmission film. The housing has a bore through which an object is inserted, and a scan mechanism for x-ray CT imaging. The light projector is provided inside the housing and configured to emit a visible light beam. The transmission film is attached to an inner wall of the housing that faces the bore, and allows the visible light beam emitted from the light projector to pass through. The transmission film has a color in a wavelength band that allows the visible light beam to pass through, and reduces the visibility of the inside of the housing from the outside, where the wavelength band excludes a wavelength of a color of the visible light beam.
