hand the tent poles 12 connected to the support poles 140 are upwardly expanded in this instance while the compression spring 170 compressed inside the hollow interior 132 of the main body 130 is expanded the tent poles 12 connected to the support poles 140 can be easily expanded in the upward direction even by a small external force transferred from the user 39 s hand here when the tent poles 12 connected to the support poles 140 are expanded upwardly the sliding member 120 slides down and the joint bar 150 hinge coupled to the sliding member 120 evenly at regular intervals in a radial direction moves downwardly moreover while the first and second connection bars 152 and 154 that respectively have one end of which is hinge coupled with the joint bar 150 and the other end of which is connected to the support poles 140 and the main body 130 are expanded in the upward direction that the support poles 140 are expanded the support poles 140 the joint bar 150 the first and second connection bar 152 and 154 which are in a folded state are rotated and expanded upwardly after that in the state that the support poles 140 are expanded at a predetermined angle for instance within a range of 70 degrees to 80 degrees relative to the main body.