A hydraulic circuit (11) of a hydraulic excavator (1) is provided with a main hydraulic circuit (11A) including a boom cylinder (5D), a pilot hydraulic circuit (11B) for operating the boom cylinder (5D) and a recovery hydraulic circuit (11C) including an accumulator (29). In this case, the recovery hydraulic circuit (11C) is provided with a recovery control valve (31) that recovers pressurized oil discharged from the boom cylinder (5D) to the accumulator (29), a main supply control valve (34) for supplying pressurized oil accumulated in the accumulator (29) to the main hydraulic circuit (11A) and a pilot supply control valve (37) for supplying pressurized oil accumulated in the accumulator (29) to the pilot hydraulic circuit (11B).