The galactolipid M-5, which showed anti-inflammatory activity is glycoglycerolipid isolated from the Okinawa marine sponge Phyllospongia foliascens. Glycolipids have been synthesized by various methods, especially it were generally known that synthetic method of M-5 analogue and synthetic method of various glycolipids by glycosidation after synthesis of glycerolipid part. The others, it was not suggested that synthetic method via glycosylglycerol obtained by degradation from diglycoside. This study was carried out to investigate the synthesis of galactosylglycerol from melibiose as M-5 intermediate. Synthesis of galactosylglycerol was accomplished by selective protection of hydroxy group of sugar and diol cleavage by Pb(OAc)$_4$. As a result, galactosylglycerol was synthesized by 8 steps pathway and their structures were elucidated by analysis instrument.