A power transmitting apparatus comprising: an input shaft, a plurality of gear stage clutch means (3a, 3b) to be arranged on the way of a power transmitting path between an engine and the wheels, the input from the input shaft of the engine side and the output to the wheel side of the gear stage clutch means (3a, 3b) being set at predetermined gear ratios; and a gear stage selecting means being able to select any one of the gear stage clutch means (3a, 3b) in use in accordance with the running condition of a vehicle and to arbitrarily set the gear ratio during power transmission from the engine to the wheels; wherein each of said gear stage clutch means comprises alternately arranged driving clutch discs (3aa, 3ba) and driven clutch discs (3ab, 3bb), hydraulic pistons (Pa, Pb, Pc, Pd, Pe, Pf) actuated by hydraulic oil to selectively engage or disengage the driving clutch discs (3aa, 3ba) and driven clutch discs (3ab, 3bb), hydraulic chambers (S1, S2, S3, S4) for actuating the hydraulic pistons (Pa, Pb, Pc, Pd, Pe, Pf), and supplying ports (P1, P2) communicating with oil passages (7a, 8a) formed within the input shaft and opening on the side surface of the input shaft for supplying the hydraulic chambers (S1, S2, S3, S4) with hydraulic oil from the oil passages (7a, 8a) to actuate the hydraulic pistons (Pa, Pb, Pc, Pd, Pe, Pf); wherein the power can be transmitted at a predetermined gear ratio with engaging the driving clutch discs (3aa, 3ba) with driven clutch discs (3ab, 3bb) of the gear stage clutch means (3a, 3b) of an arbitrary gear stage by selectively supplying hydraulic oil to the hydraulic chambers (S1, S2, S3, S4); and wherein a plurality of the supplying ports (P1, P2) are formed on a same plane of a radial cross-section of the input shaft characterized in that an annular sealing member (D1, D2) is arranged around each of the supplying ports (P1, P2) formed on the outer circumferential surface of the input shaft so as to enclose and seal the supplying ports (P1, P2); and in that said sealing member (D1, D2) is previously formed to have a bent configuration so that it corresponds to the radius of curvature of the outer circumferential surface of the input shaft. an input shaft, a plurality of gear stage clutch means (3a, 3b) to be arranged on the way of a power transmitting path between an engine and the wheels, the input from the input shaft of the engine side and the output to the wheel side of the gear stage clutch means (3a, 3b) being set at predetermined gear ratios; and a gear stage selecting means being able to select any one of the gear stage clutch means (3a, 3b) in use in accordance with the running condition of a vehicle and to arbitrarily set the gear ratio during power transmission from the engine to the wheels; wherein each of said gear stage clutch means comprises alternately arranged driving clutch discs (3aa, 3ba) and driven clutch discs (3ab, 3bb), hydraulic pistons (Pa, Pb, Pc, Pd, Pe, Pf) actuated by hydraulic oil to selectively engage or disengage the driving clutch discs (3aa, 3ba) and driven clutch discs (3ab, 3bb), hydraulic chambers (S1, S2, S3, S4) for actuating the hydraulic pistons (Pa, Pb, Pc, Pd, Pe, Pf), and supplying ports (P1, P2) communicating with oil passages (7a, 8a) formed within the input shaft and opening on the side surface of the input shaft for supplying the hydraulic chambers (S1, S2, S3, S4) with hydraulic oil from the oil passages (7a, 8a) to actuate the hydraulic pistons (Pa, Pb, Pc, Pd, Pe, Pf); wherein the power can be transmitted at a predetermined gear ratio with engaging the driving clutch discs (3aa, 3ba) with driven clutch discs (3ab, 3bb) of the gear stage clutch means (3a, 3b) of an arbitrary gear stage by selectively supplying hydraulic oil to the hydraulic chambers (S1, S2, S3, S4); and wherein a plurality of the supplying ports (P1, P2) are formed on a same plane of a radial cross-section of the input shaft characterized in that an annular sealing member (D1, D2) is arranged around each of the supplying ports (P1, P2) formed on the outer circumferential surface of the input shaft so as to enclose and seal the supplying ports (P1, P2); and in that said sealing member (D1, D2) is previously formed to have a bent configuration so that it corresponds to the radius of curvature of the outer circumferential surface of the input shaft.