To provide a seat base for a patient on which a subject can be easily placed, a bed device, and a medical image diagnostic device.SOLUTION: A seat base 10 for a patient includes a seat base part 11 on which a subject is seated and a support part 82 connected to a top plate of a bed device for supporting the seat base part horizontally rotatably with respect to the top plate. The seat base for a patient also includes a first support member 13 and a second support member 12 for supporting the subject connected to an edge of the seat base part rotatably with respect to the base end part. An angle of the first support member and an angle of the second support member can be adjusted so that the top of the seat base part, the top surface of the first support member, and the top surface of the second support member form substantially the same plane.SELECTED DRAWING: Figure 4【課題】被検体の載置が容易な患者用座台、寝台装置および医用画像診断装置を提供する。【解決手段】患者用座台１０は、被検体が着座する座台部１１と、寝台装置の天板に結合され、天板に対して座台部を水平回転可能に支持する支持部８２と、を備える。また、座台部の縁部に座台部に対して回転可能に結合され、被検体を支持する第１サポート部材１３および第２サポート部材１２を備え、座台部の上と、第１サポート部材の上面と、第２サポート部材の上面とが略同一平面をなすように、第１サポート部材の角度と前記第２サポート部材の角度とが調整可能である。【選択図】図４
