PURPOSE: To make a window in the side having no door to be openable with a light weight and simple construction by disposing a window plate slidable in the fore-aft direction and aplacing the window plate to overlap a rear pillar when opened.

CONSTITUTION: The left hand side side plate has a door opening to get in and out, and a door 28 is attached thereto with a hinge for opening sideward. The vehicle body 14 has in its right hand side a front and a rear pillars 24, 26 and a nearly trapezoidal opening 36 defined by a right hand side plate 20 and a roof plate 22. A window frame 36 is attached from the window opening 36 to the inside of the rear pillar 26. The window frame 38 has two window plates 40 in it which are slidable in the window frame 38 in the fore-aft direction. Therefore, when the window plate 40 is slid forward, the window opening 36 can be closed completely, and when slid rearward to overlap the rear pillar 26, the window opening 36 can be opened widely.