A hydraulic system includes a first supply line connecting a boom control valve and a bottom side of a boom cylinder, a second supply line connecting the boom control valve and a rod side of the boom cylinder, a leveling switch valve having: a first operating position allowing a leveling operation of a working tool; and a first stopping position allowing the leveling operation to stop, a ride controller including: a ride-control switch valve connected to a branched fluid line branched from the first supply line; and an accumulator configured to perform an anti-vibrating operation for suppressing a pressure fluctuation of the boom cylinder, and a drain fluid line to discharge operation fluid in a downstream section extending from the leveling switch valve to the rod side of the boom cylinder in the second supply line when the leveling switch valve is switched to the first stopping position.