To provide a window shade for a rear window part of a rear side part window.

This window shade 22 for a triangular window 18 of the rear side part door 7, actually has a guide rail 24 extending in a straight line over the whole lower edge part 19. A pocket is included in the vicinity of a winding shaft 23, or here, the guide rail 24 becomes an obliquely extending part 34 after a short transfer circular arc. A slide body 39 of a slide part 25 traveling by passing through the guide rail 24 is turned thereby, and a continuously connected arm 41 of the slide part 25 is arranged in parallel to a window post.