In the present invention a hydraulic circuit (11) in a hydraulic shovel (1) comprises: a main hydraulic circuit (11A) that includes a boom cylinder (5D); a pilot hydraulic circuit (11B) for operatingthe boom cylinder (5D); and an oil recovery circuit (11A) that includes an accumulator (29). In this case, the oil recovery circuit (11C) comprises: a recovery control valve (31) for returning to theaccumulator (29) pressurized oil discharged from the boom cylinder (5D); a main supply control valve (34) for supplying pressurized oil that has accumulated in the accumulator (29) to the main hydraulic circuit (11A); and a pilot supply control valve (37) for supplying pressurized oil that has accumulated in the accumulator (29) to the pilot hydraulic circuit (11B).