To perform transfer of a substance to be treated in and out of a furnace in a short time.

In this method for transferring a substance to be treated in and out of a furnace, the substance P before treatment is placed on a treatment object substance support table 3 which is arranged in a heat treatment room R provided within a furnace 1 and besides has treatment object substance placement positions where a plurality of the substances P to be treated and a placed in such a state as to be spaced apart vertically, and the substances P after treatment are taken out of the support 3. The action of placing the substance P to be treated on the vacant placement position in condition that at least one placement position is vacant, and next, taking out the substance P to be treated at the point of time when the treatment time has passed out of the substances P to be treated placed on the support 3 is repeated. After placement of the substance P to be treated last on support 3, the one at the point of time when the treatment time has passed is taken out of the substances P to be treated placed on the support 3 without placing a new substance P to be treated.