A 3D inkjet printer capable of printing on a surface of a medium of a three-dimensional shape by discharging ink from an inkjet head while moving a medium holding unit that holds the medium and the inkjet head relative to each other, the 3D inkjet printer comprising: a Y-axial driving unit capable of moving the inkjet head along a Y-axial direction, the Y-axial direction being a main scanning direction; a Z-axial supporting unit that supports the medium holding unit so as to be movable along a Z-axial direction, the Z-axial direction being a hoisting direction that is perpendicular to the Y-axial direction; an X-axial driving unit capable of moving the Z-axial supporting unit along an X-axial direction, the X-axial direction being perpendicular to the Y-axial direction and the Z-axial direction; and a Z-axial driving unit capable of moving the medium holding unit along the Z-axial direction, an arm unit (42a, 42b) comprising an end, the arm unit being supported by the Z-axial supporting unit and jutting out in the X-axial direction, wherein the medium holding unit includes an A-axial driving unit capable of swinging the medium along an A-axial direction, the A axial direction being a rotational direction about a shaft disposed along the Y-axial direction, a B-axial driving unit capable of rotating the medium along a B-axial direction, the B-axial direction being a rotational direction about a shaft disposed perpendicular to the Y-axial direction, characterized by further comprising: an A-axialrotating unit that is mounted on a rotating shaft mounted on the end of the arm unit, that is supported by the end of the arm unit and that is swung in the A-axial direction by the A-axial driving unit, and a medium mounting unit that holds the medium, and that is mounted on the A-axial rotating unit and rotated in the B-axial direction by the B-axial driving unit. a Y-axial driving unit capable of moving the inkjet head along a Y-axial direction, the Y-axial direction being a main scanning direction; a Z-axial supporting unit that supports the medium holding unit so as to be movable along a Z-axial direction, the Z-axial direction being a hoisting direction that is perpendicular to the Y-axial direction; an X-axial driving unit capable of moving the Z-axial supporting unit along an X-axial direction, the X-axial direction being perpendicular to the Y-axial direction and the Z-axial direction; and a Z-axial driving unit capable of moving the medium holding unit along the Z-axial direction, an arm unit (42a, 42b) comprising an end, the arm unit being supported by the Z-axial supporting unit and jutting out in the X-axial direction, wherein the medium holding unit includes an A-axial driving unit capable of swinging the medium along an A-axial direction, the A axial direction being a rotational direction about a shaft disposed along the Y-axial direction, a B-axial driving unit capable of rotating the medium along a B-axial direction, the B-axial direction being a rotational direction about a shaft disposed perpendicular to the Y-axial direction, characterized by further comprising: an A-axialrotating unit that is mounted on a rotating shaft mounted on the end of the arm unit, that is supported by the end of the arm unit and that is swung in the A-axial direction by the A-axial driving unit, and a medium mounting unit that holds the medium, and that is mounted on the A-axial rotating unit and rotated in the B-axial direction by the B-axial driving unit.