The disclosure provides an anti-lock brake device including an oil pressure tank, a valve, and a movable component. The oil pressure tank has an accommodation space, an oil inlet channel, and an oil outlet channel connected to the accommodation space. The valve is slidably located in the oil inlet channel and for sealing or opening an oil inlet of the oil inlet channel. The movable component is located in the accommodation space and has a connecting channel corresponding to the oil inlet and an oil outlet of the oil outlet channel. When the movable component is slid to a depressurized position, the movable component is moved away from the valve for sealing the oil inlet, a first volume is produced between the connecting channel and the oil inlet, and a second volume, smaller than the first volume, is removed from between the connecting channel and the oil outlet.