An electric valve (1, 1A, 1B) comprising: a valve main body that includes a valve chamber for accommodating a valve body; a can connected to the valve main body; a support shaft that rotatably supports a rotor of a motor; a rotor support member (56, 56B); a conversion mechanism for displacing the valve body and the support shaft in an axial direction in accordance with a rotation angle of the rotor; a reduction mechanism for reducing a rotation of the rotor and transmitting the rotation to the conversion mechanism; wherein said reduction mechanism comprises a first-stage reduction portion and a second-stage reduction portion arranged coaxially and connected in series, the first-stage reduction portion including, on the inner circumferential side of the rotor, a sun gear integrally formed with the rotor support member, a fixed ring gear, an upper portion thereof being attached to the upper portion of the valve main body and extending upward, a planetary gear disposed between the sun gear and the fixed ring gear and meshing with each, and a carrier rotatably supporting the planetary gear, the second-stage reduction portion including a sun gear which is integral with the carrier and is rotatably supported with respect to the support shaft, a lower portion of the fixed ring gear, a planetary gear which is disposed between the sun gear and the fixed ring gear and meshes with each, a carrier for rotatably supporting the planetary gear, and a closed-bottom cylindrical output gear member having teeth on its inner circumference that mesh with the planetary gear, a shaft support portion for supporting the support shaft so as to be movable in at least an axial direction with respect to the can; and a buffer portion disposed between an end portion of the support shaft and the can along an axial direction, wherein in the valve-closed state, where A is the axial direction minimum distance between the buffer portion and the upper end of the support shaft, B is the axial direction minimum distance between the lower surface of the shaft support portion and the upper surface of the rotor support member (56, 56B), and C is the axial direction minimum distance between the lower surface of the fixed ring gear and the upper surface of the output gear member, the following relational expression is established: A < C, A < B, and B ≦ C. a valve main body that includes a valve chamber for accommodating a valve body; a can connected to the valve main body; a support shaft that rotatably supports a rotor of a motor; a rotor support member (56, 56B); a conversion mechanism for displacing the valve body and the support shaft in an axial direction in accordance with a rotation angle of the rotor; a reduction mechanism for reducing a rotation of the rotor and transmitting the rotation to the conversion mechanism; wherein said reduction mechanism comprises a first-stage reduction portion and a second-stage reduction portion arranged coaxially and connected in series, the first-stage reduction portion including, on the inner circumferential side of the rotor, a sun gear integrally formed with the rotor support member, a fixed ring gear, an upper portion thereof being attached to the upper portion of the valve main body and extending upward, a planetary gear disposed between the sun gear and the fixed ring gear and meshing with each, and a carrier rotatably supporting the planetary gear, the second-stage reduction portion including a sun gear which is integral with the carrier and is rotatably supported with respect to the support shaft, a lower portion of the fixed ring gear, a planetary gear which is disposed between the sun gear and the fixed ring gear and meshes with each, a carrier for rotatably supporting the planetary gear, and a closed-bottom cylindrical output gear member having teeth on its inner circumference that mesh with the planetary gear, a shaft support portion for supporting the support shaft so as to be movable in at least an axial direction with respect to the can; and a buffer portion disposed between an end portion of the support shaft and the can along an axial direction, wherein in the valve-closed state, where A is the axial direction minimum distance between the buffer portion and the upper end of the support shaft, B is the axial direction minimum distance between the lower surface of the shaft support portion and the upper surface of the rotor support member (56, 56B), and C is the axial direction minimum distance between the lower surface of the fixed ring gear and the upper surface of the output gear member, A is the axial direction minimum distance between the buffer portion and the upper end of the support shaft, B is the axial direction minimum distance between the lower surface of the shaft support portion and the upper surface of the rotor support member (56, 56B), and C is the axial direction minimum distance between the lower surface of the fixed ring gear and the upper surface of the output gear member,