It is very important to make mounting numerous silkworms by their normal growth when considering the sericultural management. There were several studies on the utilization of repellent to the matured silkworms to mounting, studies concerning forcing maturity of silkworms were developed considerably after studies on the insect ecdysis hormone. Commercial named MSH(II) (Inoksterone) similar substance of ecdysterone and DAT repellent (Dodesil alcohl) were used for this study, and the results can be summarized as follows; 1. MSH (II) mixed with the mulberry leaves shown the matured effect on the growth of silkworms and increased amount of MSH (II) shortened the last stage in their growth. 2. MSH (II) mixed with the mulberry leaves when 5% of early matured silkworms appeared were most effective. 3. DAT was hastened their mounting. 4. Utilization of MSH (II) and DAT together were hastened silkworms mounting and those chemicals can be used practically in the silkworm rearing.