To provide a rigid and elegant sash frame with a transom, for a synthetic resin sash having even a screen-door rail integrated therewith, while avoiding variations among finished products.

This sash frame structure includes a rectangular frame surrounded by two jamb members 1, 1, a lintel member 2 and a threshold member 3 and divided by a transom 4 either horizontally or vertically or both, with sashes 5 fitted into rectangular sections divided from one another. The jambs 1 and 1, the lintel 2 and the threshold 3 including the transom 4 are integrally molded from synthetic resin to constitute the transom 4. Screen-door rails 8, 8 and so forth are also integrally molded on the outsides of the jamb members 1 and 1, the lintel member 2, the threshold member 3 and the transom 4. Long metallic members of rectangular cross section are either insert molded into the transom member 4 and the frame members 1, 2 and 3 as cores 7 or are inserted into core portions after being molded.