A sealing and pump-up device (10) includes: a liquid agent container (18) containing a sealing agent (32); an injection unit (20) that is connected to an outlet (29) of the liquid agent container (18) and has a liquid pressurization and supply chamber (40) and a jig insertion hole (44); a jig (82) that by insertion into the jig insertion hole (44) pierces an aluminum seal (30) by means of a piercing member (62) and closes off the jig insertion hole (44); and a leading end portion (85), of an insertion portion (84), having a step (85A) that catches on an edge (44B) of a jig insertion hole (44) before the jig (82) that has been inserted into the jig insertion hole (44) reaches a piercing position, when the aluminum seal (30) is pierced.