To provide a door easy in adjusting the height, superior in fixation reliability, and having a nonslip stopper.

This sliding door has the nonslip stopper capable of adjusting the height. The nonslip stopper has a body, a locking block and an adjusting block. The adjusting block abuts on an upper frame in floating of the door. The body has a fitting groove and a fixing part to the door. The locking block has a box-shaped part, and has an engaging part with the fitting groove of the body on the outside, and has a unevenness on the inside in a point symmetric manner. The adjusting block can be installed in the box-shaped part of the locking block by changing the direction of the horizontal direction, and has a unevenness in a point symmetric manner by making the depth different for abutting so as to become different in an abutting surface with an upper surface of the unevenness of the locking block when changing the direction of the horizontal direction.