Cover material terminal treating member, seat part, and vehicle seat

There is provided a long-life and strong cover material terminal treating member in which the terminal treatment of a cover material is easy to perform, and the terminal of the cover material is less liable to be taken away by a force from the outside, and which can withstand a long-time use. The cover material terminal treating member 10 for a seat part in which a cushion material 23 is covered with a cover material 24 includes a retaining plate 17 fixed to the terminal of the cover material 24a and a retaining clip 11 for storing the retaining plate 17. The retaining clip 11 includes a first wall part 12 fixed at a position different from the terminal of the cover material 24a, a second wall part 14 facing to the first wall part 12, and a connecting part 13 for connecting the two wall parts 12 and 14 to each other. In the end part of the second wall part 14, a retaining claw 16 bent at an acute angle and being in contact with one end side of the retaining plate 17 is erectingly provided. In the first wall part 12, a protrusion 15 in contact with the other end side of the retaining plate 17 is erectingly provided. The protrusion 15 is provided on the opening 19 side of a position at which the retaining plate 17 is in contact with the first wall part 12.