A rotation transmission device comprising an input shaft, an output shaft arranged coaxial with the input shaft, a housing covering end portions of the input shaft and the output shaft, a two-way clutch mounted in the housing and configured to selective transmit torque from the input shaft to the output shaft, and an electromagnetic clutch configured to selectively engage and disengage the two-way clutch, wherein the two-way clutch comprises: an outer ring provided at the end portion of the output shaft and having an inner periphery; an inner ring provided at the end portion of the input shaft and having an outer periphery; a control retainer including a plurality of circumferentially spaced apart first bars; a rotary retainer including a plurality of circumferentially spaced apart second bars, wherein the first and second bars (22, 26) are disposed between the inner periphery of the outer ring and the outer periphery of the inner ring, with the first bars disposed between respective circumferentially adjacent pairs of second bars, thereby defining pockets between the respective first bars and the second bars circumferentially adjacent to the respective first bars; a plurality of opposed pairs of engaging elements (15, 46), each opposed pair of the engaging elements (15, 46) being mounted in one of the pockets; and elastic members mounted between the respective opposed pairs of engaging elements (15, 46) and biasing the opposed pairs of engaging elements (15, 46) toward positions where the engaging elements (15, 46) engage the inner periphery of the outer ring and the outer periphery of the inner ring, wherein the rotation transmission device further comprises an annular spring holder kept in abutment with a first end surface of the inner ring located close to an opening of the outer ring so as to rotate together with the input shaft, the spring holder including spring support pieces provided on an outer periphery of the spring holder and configured to prevent radially outward movement of the respective elastic members, wherein the electromagnetic clutch comprises an armature connected to the control retainer and movable in an axial direction of the input shaft, and an electromagnet including an electromagnetic coil supported by a yoke, wherein the electromagnetic clutch is configured to move the control retainer in the axial direction through the armature when the electromagnet is energized, thereby rotating the control retainer and the rotary retainer relative to each other in a direction in which circumferential widths of the pockets decrease, and disengaging the engaging elements (15, 46), characterized in that the spring support pieces are plate-shaped members disposed radially outwardly of the respective elastic members to extend in the axial direction in parallel to an outer periphery of the input shaft, wherein gaps are defined between distal ends of the spring support pieces and the outer periphery of the input shaft such that the elastic members can be inserted through the gaps. an outer ring provided at the end portion of the output shaft and having an inner periphery; an inner ring provided at the end portion of the input shaft and having an outer periphery; a control retainer including a plurality of circumferentially spaced apart first bars; a rotary retainer including a plurality of circumferentially spaced apart second bars, wherein the first and second bars (22, 26) are disposed between the inner periphery of the outer ring and the outer periphery of the inner ring, with the first bars disposed between respective circumferentially adjacent pairs of second bars, thereby defining pockets between the respective first bars and the second bars circumferentially adjacent to the respective first bars; a plurality of opposed pairs of engaging elements (15, 46), each opposed pair of the engaging elements (15, 46) being mounted in one of the pockets; and elastic members mounted between the respective opposed pairs of engaging elements (15, 46) and biasing the opposed pairs of engaging elements (15, 46) toward positions where the engaging elements (15, 46) engage the inner periphery of the outer ring and the outer periphery of the inner ring,