A fitting comprising: a frame body including a lower frame provided with a track; a fixed plate member arranged on an outdoor side of the frame body, the fixed plate member including a panel having a lower edge part supported by the lower frame; and a movable plate member arranged on an indoor side of the frame body, the movable plate member being slidable in a longitudinal direction of the lower frame along the track, wherein the lower frame includes an inner lower frame part on which the track is arranged, an outer lower frame part supporting a surface facing an outdoor side of the panel, and an intermediate lower frame part positioned between the inner lower frame part and the outer lower frame part, a covering member is arranged at a portion of the lower frame closer to an outdoor side of the fitting than the movable plate member, the covering member including an upper surface part covering a portion between the outer lower frame part and the movable plate member and a leg part that extends downward from the upper surface part and is supported by the intermediate lower frame part, and the intermediate lower frame part and the inner lower frame part are separated from each other and an inner connecting member having an insulating property is interposed between the intermediate lower frame part and the inner lower frame part, and the intermediate lower frame part and the outer lower frame part are separated from each other and an outer connecting member having an insulating property is interposed between the intermediate lower frame part and the outer lower frame part, wherein a decorative material is arranged on an upper surface positioned on an indoor side of the lower frame, and wherein a support member having an insulating property is interposed between the decorative material and the inner connecting member, the support member is arranged to connect between an upper end of the intermediate lower frame part and an upper end of the inner lower frame part, and the inner connecting member is in intimate contact with a lower surface of the support member. a frame body including a lower frame provided with a track; a fixed plate member arranged on an outdoor side of the frame body, the fixed plate member including a panel having a lower edge part supported by the lower frame; and a movable plate member arranged on an indoor side of the frame body, the movable plate member being slidable in a longitudinal direction of the lower frame along the track, wherein the lower frame includes an inner lower frame part on which the track is arranged, an outer lower frame part supporting a surface facing an outdoor side of the panel, and an intermediate lower frame part positioned between the inner lower frame part and the outer lower frame part, a covering member is arranged at a portion of the lower frame closer to an outdoor side of the fitting than the movable plate member, the covering member including an upper surface part covering a portion between the outer lower frame part and the movable plate member and a leg part that extends downward from the upper surface part and is supported by the intermediate lower frame part, and the intermediate lower frame part and the inner lower frame part are separated from each other and an inner connecting member having an insulating property is interposed between the intermediate lower frame part and the inner lower frame part, and the intermediate lower frame part and the outer lower frame part are separated from each other and an outer connecting member having an insulating property is interposed between the intermediate lower frame part and the outer lower frame part, wherein a decorative material is arranged on an upper surface positioned on an indoor side of the lower frame, and wherein a support member having an insulating property is interposed between the decorative material and the inner connecting member, the support member is arranged to connect between an upper end of the intermediate lower frame part and an upper end of the inner lower frame part, and the inner connecting member is in intimate contact with a lower surface of the support member.