To provide a new fastener for a bag and a pouch such as a bag and a suitcase in which a contrivance or the like is executed to the reinforcement of the closed state maintaining force of a lid or the like.

This fastener is constituted of a receiving body 3 provided with a recessed part on the surface built-in a magnet 11 and a hooking body 5 provided with a projection part to be fitted to the recessed part at the time of being attracted by the attraction force of the magnet 11 on the surface of an attraction plate 20. In this case, it is provided with a cylindrical projection edge part provided on the receiving body 3 in the state of surrounding the outer periphery of the attraction plate 20 when the attraction plate 20 is attracted to the receiving body 3, an inward edge part 17 for hooking provided on a part narrower than the half of the entire length of the upper edge of the cylindrical projection edge part, an insertion port 18 of the attraction plate 20 formed by a hole 13 surrounded by the part other than the part provided with the edge part 17 for hooking at the upper edge of the cylindrical projection edge part and by the tip of the edge part 17 for hooking and a hooking edge part 24 to the edge part 17 for hooking formed by a raising bulk member 23 at the outer peripheral edge of the attraction plate 20 of the hooking body 5.