An anchor bolt to be fixed in a bore provided in a wall surface, comprising: a cylindrical rod having on its outer peripheral surface an external thread, and an expandable device disposed on the rod for fixing the anchor bolt on an inner peripheral surface of the bore; wherein the expandable device has a taper member and an expandable member assembled so as to be fitted over the taper member, the taper member having an internal thread formed along a central axis of the taper member for being threadably engaged with the external thread of the rod and a plurality of planar inclined surfaces of an outer peripheral surface of the taper member, wherein the expandable member has a plurality of abutment parts and a bridge connecting tips of the abutment parts with each other, the abutment part having a planar inner surface which can surface-contact the inclined surface of the taper member, wherein each inclined surface of the taper member is inclined so as to go away from the central axis of the taper member toward a tip of the anchor bolt, and wherein when the taper member is moved toward a base end of the bore in a state in which the anchor bolt is inserted into the bore, the inclined surface of the taper member is surface-pressed against the inner surface of the abutment part and an outer peripheral surface of the abutment part is pressed against the inner peripheral surface of the bore, characterized in that the tip of the taper member has a tip peripheral surface which is located adjacent to and on the tip side of the inclined surface and is formed as an upright surface along the central axis of the taper member. a cylindrical rod having on its outer peripheral surface an external thread, and an expandable device disposed on the rod for fixing the anchor bolt on an inner peripheral surface of the bore; wherein the expandable device has a taper member and an expandable member assembled so as to be fitted over the taper member, the taper member having an internal thread formed along a central axis of the taper member for being threadably engaged with the external thread of the rod and a plurality of planar inclined surfaces of an outer peripheral surface of the taper member, wherein the expandable member has a plurality of abutment parts and a bridge connecting tips of the abutment parts with each other, the abutment part having a planar inner surface which can surface-contact the inclined surface of the taper member, wherein each inclined surface of the taper member is inclined so as to go away from the central axis of the taper member toward a tip of the anchor bolt, and wherein when the taper member is moved toward a base end of the bore in a state in which the anchor bolt is inserted into the bore, the inclined surface of the taper member is surface-pressed against the inner surface of the abutment part and an outer peripheral surface of the abutment part is pressed against the inner peripheral surface of the bore, characterized in that the tip of the taper member has a tip peripheral surface which is located adjacent to and on the tip side of the inclined surface and is formed as an upright surface along the central axis of the taper member.