A placing table includes a measuring-unit that measures a vertical position of an orifice member placed on the placing table, a position-regulating-portion that engages with a part of the orifice member of a type corresponding to the table, and an orifice-member-determination-unit that determines a placed state and type of the orifice member based on a measurement result obtained by the measuring-unit. When the corresponding type of the orifice member is placed in a correct posture, the position-regulating-portion engages with the orifice member and seats the orifice member on the table over the entire circumference of the lower end portion thereof. When a different type of orifice member is placed or when the corresponding type of orifice member is placed in an incorrect posture, the position-regulating-portion does not engage with the orifice member and lifts at least a part of the orifice member from the table.