To provide a right side wall with excellent appearance by solving a problem wherein a decorative sheet 67 is provided separately from a right panel, the number of parts is increased, a work such as welding is required, and manufacturing cost of a cab is increased.

The decorative sheet projecting from a lower side edge of a window frame of the right panel toward inside upward is formed integrally with the right panel. An erecting surface of the decorative sheet is formed to be overlapped with a part of window glass and separated from the window glass toward a rear side, to secure visual field in a lower part at a front end of the window glass.