A sash comprising: a first planar material (211, 311; 4211) and a second planar material (212, 312; 4212) that have rectangular shapes having identical outside dimensions to each other, and are bonded to each other with a heat-insulating space (215, 315; 4215) held therebetween by interposing a spacer member (214, 314; 4214) between peripheral ends of the first and the second planar materials; and a third planar material (213, 313; 4213) that has a rectangular shape having smaller outside dimensions than those of the first planar material (211, 311; 4211), and is bonded to the first planar material (211, 311; 4211) with a heat-insulating space (217, 317; 4217) held between the third planar material (213, 313; 4213) and the first planar material (211, 311; 4211) by interposing a spacer member (216, 316; 4216) at peripheral ends of the third planar material (213, 313; 4213), characterized in that an end of at least one side of the third planar material (213, 313, 4213) lying on an identical plane to that of the first planar material (211, 311, 4211), and that rail and stile members (22, 23, 24, 32, 33, 34, 422, 423, 424) are bonded to a surface of the first planar material (211, 311; 4211) at peripheral ends where end faces of the first planar material (211, 311; 4211) project more than end faces of the third planar material (213, 313; 4213), and that a rail or stile member (25, 35, 425) is bonded to a surface of the third planar material (213, 313; 4213) at said peripheral end where the end face of the first planar material (211, 311; 4211) aligns with an end face of the third planar material (213, 313; 4213). a first planar material (211, 311; 4211) and a second planar material (212, 312; 4212) that have rectangular shapes having identical outside dimensions to each other, and are bonded to each other with a heat-insulating space (215, 315; 4215) held therebetween by interposing a spacer member (214, 314; 4214) between peripheral ends of the first and the second planar materials; and a third planar material (213, 313; 4213) that has a rectangular shape having smaller outside dimensions than those of the first planar material (211, 311; 4211), and is bonded to the first planar material (211, 311; 4211) with a heat-insulating space (217, 317; 4217) held between the third planar material (213, 313; 4213) and the first planar material (211, 311; 4211) by interposing a spacer member (216, 316; 4216) at peripheral ends of the third planar material (213, 313; 4213), characterized in that an end of at least one side of the third planar material (213, 313, 4213) lying on an identical plane to that of the first planar material (211, 311, 4211), and that rail and stile members (22, 23, 24, 32, 33, 34, 422, 423, 424) are bonded to a surface of the first planar material (211, 311; 4211) at peripheral ends where end faces of the first planar material (211, 311; 4211) project more than end faces of the third planar material (213, 313; 4213), and that a rail or stile member (25, 35, 425) is bonded to a surface of the third planar material (213, 313; 4213) at said peripheral end where the end face of the first planar material (211, 311; 4211) aligns with an end face of the third planar material (213, 313; 4213).