A slide fastener element polishing device (1, 101) for polishing a fastener element in a slide fastener which has a fastener tape and the fastener element attached to the fastener tape, the fastener element having a front surface and a back surface, the polishing device (1, 101) comprising: a transport path for the slide fastener; a support part (3, 13) arranged along the transport path and arranged to face one of the front surface and the back surface of the fastener element to support a posture of the fastener element; the support part (3, 13) comprises a support surface (34a, 134a, 139a) configured to come in contact with one of the front surface and the back surface of the fastener element; and a polishing part (2, 2a, 2b) arranged to face the support part (3, 13) across the transport path; wherein the polishing part (2, 2a, 2b) comprises a rotation shaft, and a polishing member (25, 25b) fixed to the rotation shaft and being rotatable by rotating the rotation shaft; and wherein the polishing member (25, 25b) is configured to come in contact with the other of the front surface and the back surface of the fastener element and polish the front surface or the back surface of the fastener element, characterized in that the support part (3, 13) comprises a first member (31, 131, 132) which is a first support roller (31, 131, 132) being rotatable about a rotation shaft thereof and a second member (33, 133, 138) which is a plate material arranged to face a peripheral surface of the first member (31, 131, 132), a gap for allowing the fastener tape to pass therethrough is provided between the first member (31, 131, 132) and the second member (33, 133, 138), a guide groove (34, 134, 139) for receiving the fastener elements therein and guiding movement of the fastener elements is formed on the peripheral surface of the first member (31, 131, 132) so as to extend in a circumferential direction of the first member (31, 131, 132), wherein a bottom surface of the guide groove (34, 134, 139) is the support surface (34a, 134a, 139a), and the rotation shaft of the first member (31, 131, 132) extends in a direction perpendicular to the rotation shaft of the polishing part (2, 2a, 2b). a transport path for the slide fastener; a support part (3, 13) arranged along the transport path and arranged to face one of the front surface and the back surface of the fastener element to support a posture of the fastener element; the support part (3, 13) comprises a support surface (34a, 134a, 139a) configured to come in contact with one of the front surface and the back surface of the fastener element; and a polishing part (2, 2a, 2b) arranged to face the support part (3, 13) across the transport path; wherein the polishing part (2, 2a, 2b) comprises a rotation shaft, and a polishing member (25, 25b) fixed to the rotation shaft and being rotatable by rotating the rotation shaft; and wherein the polishing member (25, 25b) is configured to come in contact with the other of the front surface and the back surface of the fastener element and polish the front surface or the back surface of the fastener element, characterized in that the support part (3, 13) comprises a first member (31, 131, 132) which is a first support roller (31, 131, 132) being rotatable about a rotation shaft thereof and a second member (33, 133, 138) which is a plate material arranged to face a peripheral surface of the first member (31, 131, 132), a gap for allowing the fastener tape to pass therethrough is provided between the first member (31, 131, 132) and the second member (33, 133, 138), a guide groove (34, 134, 139) for receiving the fastener elements therein and guiding movement of the fastener elements is formed on the peripheral surface of the first member (31, 131, 132) so as to extend in a circumferential direction of the first member (31, 131, 132), wherein a bottom surface of the guide groove (34, 134, 139) is the support surface (34a, 134a, 139a), and the rotation shaft of the first member (31, 131, 132) extends in a direction perpendicular to the rotation shaft of the polishing part (2, 2a, 2b).