A construction machine comprising a traveling body, a revolving body revolvably mounted on the traveling body and a revolving drive device for revolving the revolving body on the traveling body, the revolving drive device comprising: a revolving bearing for revolvably supporting the revolving body on the traveling body; a first revolving gear member mounted on a first one of the body either the traveling body or the revolving body and positioned on the same axis as the revolving bearing; a second revolving gear member mounted on the first one of the body and positioned on the same axis as the revolving bearing; a hydraulic motor mounted on a second one of the body on which the first revolving gear is not mounted, the hydraulic motor having a first pinion gear that meshes with the first revolving gear member, the hydraulic motor being capable of rotatably driving the first pinion gear to rotatably drive the first revolving gear member; a regenerative electric motor mounted on the second one of the body on which the second revolving gear is not mounted, the regenerative electric motor having a second pinion gear that meshes with the second revolving gear member, the regenerative electric motor being capable of rotatably driving the second pinion gear to rotatably drive the second revolving gear member, and being capable of regenerative electric power generation by being driven via the second pinion gear by the rotation of the second revolving gear member; a first reduction ratio at which rotation is transmitted by the first pinion gear to the first revolving gear member being different from a second reduction ratio at which rotation is transmitted by the second pinion gear to the second revolving gear member, the revolving bearing has an outer ring attached to one of the traveling body and the revolving body, and an inner ring provided to an inner side of the outer ring so as to be able to perform relative rotation via rolling elements, the inner ring being attached to another of the traveling body and the revolving body; the first revolving gear member has a first gear being integrally connected to the inner ring, while the second revolving gear member has a second gear being integrally connected to the inner ring and having a different number of teeth with the first gear; the hydraulic motor is provided on the body on which the outer ring is mounted, and the first pinion gear meshes with the first gear; and the regenerative electric motor is provided on the body on which the outer ring is mounted and the second pinion gear meshes with the second gear; characterizing in that; either one of the first gear and second gear is configured by an internal gear formed in an inner circumferential surface of the inner ring, and another of the first gear and second gear is configured by an internal gear formed in an inner circumferential surface of a ring-shaped member integrally linked to the inner ring. a revolving bearing for revolvably supporting the revolving body on the traveling body; a first revolving gear member mounted on a first one of the body either the traveling body or the revolving body and positioned on the same axis as the revolving bearing; a second revolving gear member mounted on the first one of the body and positioned on the same axis as the revolving bearing; a hydraulic motor mounted on a second one of the body on which the first revolving gear is not mounted, the hydraulic motor having a first pinion gear that meshes with the first revolving gear member, the hydraulic motor being capable of rotatably driving the first pinion gear to rotatably drive the first revolving gear member; a regenerative electric motor mounted on the second one of the body on which the second revolving gear is not mounted, the regenerative electric motor having a second pinion gear that meshes with the second revolving gear member, the regenerative electric motor being capable of rotatably driving the second pinion gear to rotatably drive the second revolving gear member, and being capable of regenerative electric power generation by being driven via the second pinion gear by the rotation of the second revolving gear member; a first reduction ratio at which rotation is transmitted by the first pinion gear to the first revolving gear member being different from a second reduction ratio at which rotation is transmitted by the second pinion gear to the second revolving gear member, the revolving bearing has an outer ring attached to one of the traveling body and the revolving body, and an inner ring provided to an inner side of the outer ring so as to be able to perform relative rotation via rolling elements, the inner ring being attached to another of the traveling body and the revolving body; the first revolving gear member has a first gear being integrally connected to the inner ring, while the second revolving gear member has a second gear being integrally connected to the inner ring and having a different number of teeth with the first gear; the hydraulic motor is provided on the body on which the outer ring is mounted, and the first pinion gear meshes with the first gear; and the regenerative electric motor is provided on the body on which the outer ring is mounted and the second pinion gear meshes with the second gear; characterizing in that; either one of the first gear and second gear is configured by an internal gear formed in an inner circumferential surface of the inner ring, and another of the first gear and second gear is configured by an internal gear formed in an inner circumferential surface of a ring-shaped member integrally linked to the inner ring.