An intake device comprising: an intake port; a valve body which is disposed in the intake port and rotated around a rotating shaft between an opening position and a closing position includes a valve body main body and an elastically deformable seal member provided along an outer periphery of the valve body main body; and a seal surface which is integrally provided at the intake port and made up of an inner wall surface with which the seal member comes into contact at the closing position of the valve body, wherein the seal surface includes a first seal surface having a first inner contact portion which protrudes to the inside of the intake port towards the valve body side and a first outer contact portion which is located further to the opposite side to the valve body than the first inner contact portion, and a second seal surface (28, 29, 30) having a second outer contact portion (28a, 29a, 30a) without having a second inner contact portion protruding to the inside of the intake port towards the valve body side, and the seal member includes a first seal portion which comes into contact with both of the first inner contact portion and the first outer contact portion of the first seal surface in the closing position of the valve body, and a second seal portion (53d, 53e, 54c, 54d, 54e) which comes into contact with the second outer contact portion (28a, 29a, 30a) of the second seal surface in the closing position of the valve body, the valve body has a rectangular shape having four sides in a plan view, the first seal surface is provided in a portion of the inner wall surface with which a side on any one side of a side on an upstream side and a side on a downstream side extending along an extension direction of a rotating shaft of the valve body comes into contact, and the second seal surface (28, 29, 30) is provided in a portion of the inner wall surface. with which a side on the other side of the side on the upstream side and the side on the downstream side comes into contact, and a portion of the inner wall surface with which a pair of sides extending in a direction intersecting the extension direction of the rotating shaft of the valve body comes into contact. an intake port; a valve body which is disposed in the intake port and rotated around a rotating shaft between an opening position and a closing position includes a valve body main body and an elastically deformable seal member provided along an outer periphery of the valve body main body; and a seal surface which is integrally provided at the intake port and made up of an inner wall surface with which the seal member comes into contact at the closing position of the valve body, wherein the seal surface includes a first seal surface having a first inner contact portion which protrudes to the inside of the intake port towards the valve body side and a first outer contact portion which is located further to the opposite side to the valve body than the first inner contact portion, and a second seal surface (28, 29, 30) having a second outer contact portion (28a, 29a, 30a) without having a second inner contact portion protruding to the inside of the intake port towards the valve body side, and the seal member includes a first seal portion which comes into contact with both of the first inner contact portion and the first outer contact portion of the first seal surface in the closing position of the valve body, and a second seal portion (53d, 53e, 54c, 54d, 54e) which comes into contact with the second outer contact portion (28a, 29a, 30a) of the second seal surface in the closing position of the valve body, the valve body has a rectangular shape having four sides in a plan view, the first seal surface is provided in a portion of the inner wall surface with which a side on any one side of a side on an upstream side and a side on a downstream side extending along an extension direction of a rotating shaft of the valve body comes into contact, and the second seal surface (28, 29, 30) is provided in a portion of the inner wall surface. with which a side on the other side of the side on the upstream side and the side on the downstream side comes into contact, and a portion of the inner wall surface with which a pair of sides extending in a direction intersecting the extension direction of the rotating shaft of the valve body comes into contact.