A fastener for an ornament, the fastener including a housing arranged from a upper housing member having a pin passing hole for entry and exit of a pin included in an ornament, and a lower housing member having an opening portion provided at a position directly opposite to the pin passing hole, and where the housing houses: a guide of frustoconical shape inside the upper housing member of the housing having a small diameter portion and a large diameter portion, a movable operating body having a cylindrical inner member including a pin introducing passage, through which the pin is introduced via a pin introducing hole facing the pin passing hole, and a small ball holder portion of frustoconical shape having an outer peripheral surface, which contacts an inner peripheral surface of the guide, and a coil spring pressingly urging the movable operating body in a direction of the pin passing hole, wherein: the guide has a small diameter portion side of its frustoconical shape positioned at the pin passing hole side thereof, the inner member of the movable operating body has the small diameter portion of the frustoconical shape of the small ball holder portion positioned at the pin passing hole side thereof, the frustoconical inner peripheral surface of the guide and the frustoconical outer peripheral surface of the small ball holder portion are in contact while having the same taper angle in a range of 10 to 20 degrees with respect to a central axis of the guide and a central axis of the small ball holder portion, the small ball holder portion is arranged from three small balls disposed in positional relationship of opposing each other, and an embracing portion that houses the three small balls, the respective small balls are housed in the embracing portion in a manner such that the small balls, which are pushed out toward an axial center when side spherical surfaces of the small balls positioned at an outer peripheral surface side of the small ball holder portion pressure-contact the inner peripheral surface of the guide, clamp the pin as a whole by pressure contact by other side spherical surfaces of the respective small balls at positions directly facing the inserted pin, and is characterized in that: the housing houses a small diameter portion and a large diameter portion, and an other side member fixed to an outer side of the inner member and including a cylindrical column portion fixed to the inner member and a grip member continuous to the column portion and, the other side member of the movable operating body has one end side of the column portion latched to the opening portion of the lower housing member and has the grip member disposed so as to protrude from the lower housing member to an exterior of the housing, and the coil spring has a frustoconical shape having a small diameter portion at the pin passing hole side and having a large diameter portion at the opening portion side. a guide of frustoconical shape inside the upper housing member of the housing having a small diameter portion and a large diameter portion, a movable operating body having a cylindrical inner member including a pin introducing passage, through which the pin is introduced via a pin introducing hole facing the pin passing hole, and a small ball holder portion of frustoconical shape having an outer peripheral surface, which contacts an inner peripheral surface of the guide, and a coil spring pressingly urging the movable operating body in a direction of the pin passing hole, the guide has a small diameter portion side of its frustoconical shape positioned at the pin passing hole side thereof, the inner member of the movable operating body has the small diameter portion of the frustoconical shape of the small ball holder portion positioned at the pin passing hole side thereof, the frustoconical inner peripheral surface of the guide and the frustoconical outer peripheral surface of the small ball holder portion are in contact while having the same taper angle in a range of 10 to 20 degrees with respect to a central axis of the guide and a central axis of the small ball holder portion, the small ball holder portion is arranged from three small balls disposed in positional relationship of opposing each other, and an embracing portion that houses the three small balls, the respective small balls are housed in the embracing portion in a manner such that the small balls, which are pushed out toward an axial center when side spherical surfaces of the small balls positioned at an outer peripheral surface side of the small ball holder portion pressure-contact the inner peripheral surface of the guide, clamp the pin as a whole by pressure contact by other side spherical surfaces of the respective small balls at positions directly facing the inserted pin, and is characterized in that: the housing houses a small diameter portion and a large diameter portion, and an other side member fixed to an outer side of the inner member and including a cylindrical column portion fixed to the inner member and a grip member continuous to the column portion and, the other side member of the movable operating body has one end side of the column portion latched to the opening portion of the lower housing member and has the grip member disposed so as to protrude from the lower housing member to an exterior of the housing, and the coil spring has a frustoconical shape having a small diameter portion at the pin passing hole side and having a large diameter portion at the opening portion side.