PURPOSE: To enhance the drawing strength by forming slip preventing protrusions extending toward a fixed member pressing part on the side surface of a staple part.

CONSTITUTION: In a staple part 11, the tip 13 is pointed so as to be easily driven into a gypsum board, a fixed part pressing part 12 is provided on the head part of the staple part 11 so that a staple 10 may be easily driven, and the fixed part pressing part is formed a little larger than the cross sectional shape of the staple part 11 to press the member to be fixed by driving. A plurality of slip preventing protrusions 14 are formed on the side surfaces of the staple part 11, and each of which is formed into a shape extending toward the fixed member pressing part 12, in order to prevent the staple 10 from slipping from the gypsum board caused by vibration when the staple 10 is driven in the gypsum board. Therefore, the staple is does not slip caused by vibration and can be reliably fixed even if it is fixed to a brittle material.