To provide an economical sliding door and its frame by manufacturing a wear part of the sliding door by a hard material so as to be changeable to increase the durability of the sliding door and reduce production cost.

This frame structure of a sliding door consists of a door frame 10 in which upper and lower contact faces of the door frame 10 are cut to a fixed thickness, respectively, and a door frame upper change wood 11 and a door frame lower change wood 12 are fixed in the cut parts by screws so as to oppose mutually and a sliding door 20 in which a door upper reinforcing wood 21 and a door lower reinforcing wood 22 of the sliding door 20 are cut to a fixed thickness, respectively, and a door upper change wood 23 and a door lower change wood 24 are fixed in the cut parts by screws.