<p>A reliably operable sealing/pump-up device on which a jig can be simply installed and out of which the jig does not drop even when it is subjected to pressure. The sealing/pump-up device (10) has a liquid agent container (18) where a sealing agent (32) is contained; an injection unit (20) that is connected to an outlet (29) of the liquid agent container (18) and has a liquid pressurization/supply chamber (40) and a jig insertion hole (44); a jig (82) that, when inserted into the jig insertion hole (44), pierces an aluminum seal (30) by means of a piercing member (62) and closes the jig insertion hole (44); and a front end section (85) of the insertion section (84) that has a step (85A) catching on an edge (44B) of the jig insertion hole (44) before the jig (82), which is inserted in the jig insertion hole (44), reaches its piercing position at which the aluminum seal (30) is pierced. The jig (82) can be simply installed on the device and can be reliably operated because the jig (82) does not drop out of the device even if subjected to pressure.</p>
