An X-ray generation unit and an X-ray detection unit are held by an arm. Image data is generated based on X-ray projection data which is generated by the X-ray detection unit. A first support member supports the arm and rotates the arm in a first rotation direction. A second support member supports the first support member. The second support member rotates the first support member around a rotation center in a second rotation direction perpendicular to the first rotation direction. A movement unit can move the second support member in an up and down direction.