To provide a sash structure in which a suitable bottom rail is easily formed of a small number of component parts depending on a mounting condition of a sash in a building.

The sash structure is formed of a support frame 10 consisting of a head, a sill, and right and left jambs, a movable frame 20 movably supported by the support frame 10, and an upper rail 50a and the bottom rail 50b guiding the movable frame 20 along the support frame 10. The bottom rail 50b includes a rail body 55 serving as a guide for moving the movable body 20, and a floor surface connector 57 having a rise wall 58 connected to an indoor-side floor surface 70. Further the rail body 55 is connected to the floor surface connector 57 via a joint member 56 formed of a heat insulator.