This invention relates to a cab support structure for construction machine. The cab support structure has a rear beam and a front beam, which support front and rear part of cab, and a center beam located and welded between inner and outer frames of the machine. A stopper located at the corner of center beam side of the junction of rear beam and outer frame is formed box shape. The stopper has an L-shaped plate welded to the rear beam and the outer frame, and a doubling L-shaped plate welded to the L-shaped plate, rear beam, and outer frame.
