A blade system of the present invention includes: a blade angle calculating part configured to calculate sum of a forwardly tilting angle of a vehicle body with respect to a reference surface and a blade lifting angle of a lift frame with respect to a reference position; a difference angle calculating part configured to calculate a difference angle by subtracting a predetermined angle from the sum of the forwardly tilting angle and the blade lifting angle; an opening ratio setting part configured to set an opening ratio of a proportional control valve based on the difference angle; and a lift controlling part configured to control the proportional control valve in accordance with the opening ratio set by the opening ratio setting part until a predetermined period of time is elapsed after onset of dozing by a blade.