An inner hub (9) with a needle attached to a tip thereof is housed in a cylindrical body (2). The inner hub (9) includes a through-hole (22) penetrating the inner hub (9) in a radial direction of the inner hub (9), and a recessed portion (23a) formed in an outer circumferential surface (23) of the inner hub (9). An opening of the through-hole (22) and the recessed portion (23a) are connected together in a circumferential direction of the inner hub (9). A liquid flowing out from the opening of the through-hole (22) is limited so that the liquid flows along the recessed portion (23a), and the flow of the liquid moving in the circumferential direction of the inner hub (9) is promoted. As a result, the removal of air bubbles in the circumferential direction of the inner hub (9) is promoted, whereby air bubbles can be prevented from remaining on the outer circumferential surface (23) of the inner hub (9).
