An X-ray phase contrast imaging apparatus comprising: an X-ray source ; a first grating irradiated with X-rays from the X-ray source to form a self-image; a second grating irradiated with the X-rays that have passed through the first grating; a detector that detects the X-rays that have passed through the second grating; an adjustment mechanism that adjusts a position of the first grating or a position of the second grating; and a controller that acquires a pitch of Moire fringes from an image of the Moire fringes detected by the detector and controls the adjustment mechanism to adjust a misalignment of the first grating or a misalignment of the second grating in an irradiation axis direction of the X-rays or a rotation direction around the irradiation axis direction of the X-rays based on the acquired pitch of the Moire fringes, and/or controls the adjustment mechanism to adjust the misalignment of the first grating, wherein the controller acquires a misalignment amount of the first grating or a misalignment amount of the second grating in the irradiation axis direction of the X-rays or the rotation direction around the irradiation axis direction of the X-rays based on at least the acquired pitch of the Moire fringes and a pitch of the second grating, and wherein the controller adjusts the misalignment of the first grating or the misalignment of the second grating in the irradiation axis direction of the X-rays or the rotation direction around the irradiation axis direction of the X-rays based on the misalignment amount of the first grating or the misalignment amount of the second grating in the irradiation axis direction of the X-rays or the rotation direction around the irradiation axis direction of the X-rays. an X-ray source ; a first grating irradiated with X-rays from the X-ray source to form a self-image; a second grating irradiated with the X-rays that have passed through the first grating; a detector that detects the X-rays that have passed through the second grating; an adjustment mechanism that adjusts a position of the first grating or a position of the second grating; and a controller that acquires a pitch of Moire fringes from an image of the Moire fringes detected by the detector and controls the adjustment mechanism to adjust a misalignment of the first grating or a misalignment of the second grating in an irradiation axis direction of the X-rays or a rotation direction around the irradiation axis direction of the X-rays based on the acquired pitch of the Moire fringes, and/or controls the adjustment mechanism to adjust the misalignment of the first grating, wherein the controller acquires a misalignment amount of the first grating or a misalignment amount of the second grating in the irradiation axis direction of the X-rays or the rotation direction around the irradiation axis direction of the X-rays based on at least the acquired pitch of the Moire fringes and a pitch of the second grating, and wherein the controller adjusts the misalignment of the first grating or the misalignment of the second grating in the irradiation axis direction of the X-rays or the rotation direction around the irradiation axis direction of the X-rays based on the misalignment amount of the first grating or the misalignment amount of the second grating in the irradiation axis direction of the X-rays or the rotation direction around the irradiation axis direction of the X-rays. <EOS>