There are provided: front supports provided vertically in front of a cabin on a rotating frame; a plurality of rear supports provided vertically and laterally with respect to each other behind the cabin on the rotating frame; a lateral frame for connecting the upper end portions of the rear supports; and an upper frame provided above the cabin to connect the lateral frame and the front supports at a position shifted leftward from a predetermined area where an attachment is raised and lowered, where one rear support is arranged behind a hoisting axis between vertical plates, while the other rear supports are arranged in rear of the cabin, and the lateral frame is arranged laterally across the vertical plates.