A sucker includes a sucker body having a rough suction layer which includes a plurality of protrusions which are juxtaposed to each other closely, and a plurality of grooves defined between the protrusions. When the rough suction layer presses an attached face and is disposed at a negative pressure state, the sucker body is pressed toward the attached face by a normal force from the ambient air, so that the rough suction layer is compressed, and the grooves form multiple independent negative pressure or vacuum zones, to increase a negative pressure of the rough suction layer, to decrease air existing in the rough suction layer, and to reduce a vacuum leak in the rough suction layer, so as to increase an air-tightness between the rough suction layer and the attached face.