The present invention is a quartz-product baking method for baking a first quartz product and a second quartz product to remove a metal contained therein, the first and second quartz products being to be loaded into a heat-processing apparatus for heat-processing a semiconductor substrate so that at least a part of each quartz product is brought into contact with a heat-processing atmosphere of the heat-processing apparatus, the quartz-product baking method comprising the steps of: with the use of a jig including a first jig element and a second jig element that are disengageably stacked in a tier-like manner, placing the first quartz product on the first jig element, stacking the second jig element on the first jig element, and placing the second quartz product on the second jig member; placing on a lid member the jig in which the quartz products are placed in a tier-like manner, elevating the lid member to load the jig into a baking vertical vessel through a lower opening thereof, and hermetically sealing the lower opening of the baking vertical vessel with the lid member; heating an atmosphere in the baking vertical vessel; and supplying a baking gas containing a hydrogen chloride gas and a gas for enhancing reactivity of the hydrogen chloride gas, into the baking vertical vessel.