To investigate the half-degumming of raw silk, the degumming was carried out with soap or sodium carbonate or sodium bicarbonate and some mixed agents at $80^{circ}C$ for 15 and 30 minutes. With soap of 20~25%o.w.f. degumming losses were about 7~12%. Degumming losses with sodium carbonate of 2~5%o.w.f. were about 6~15%. And about 6~12% wright losses were observed in the degumming with sodium bicarbonate of 20~30%o.w.f. In the degumming with the mixed degumming agents of soap and sodium carbonate, degumming losses were 9~15% with 5%o.w.f. soap and 2~5%o.w.f. sodium carbonate. Sodium carbonate was more effective on the removal of sericin from raw silk than soap. During drying generally half degummed silk yarns stuck together to result in harsh and hard lumps by the adhesion and solidification of the residue sericin of partially degummed silk. Sodium hydrosulfite in degumming agent effectively protected the adhesion of half degummed silk yarns.