A zoom lens barrel includes a through groove which is provided on a first cylindrical member; a radial projection provided on a second cylindrical member; and a roller which is supported by the radial projection and is fitted in the through groove. The through groove has an opening width on the inner diameter of the first cylindrical member which is greater than the opening width on the outer diameter thereof. The roller is provided with an slip-off prevention portion whose diameter is greater than the opening width of the through groove on the outer diameter of the first cylindrical member, but smaller than the opening width on the inner diameter. The through groove is provided with a large width portion at which the roller is fitted into, so that the slip-off prevention portion is located in the through groove.