The control of biodegradation and the improvement of moldability of poly-L-lactide, PLA, have been difficult because of the high crystallinity and the lability of melt viscosity. The synthesis of biodegradable PLA having the branched structure, comb-type PLA, was carried out by using only metabolizable materials to obtain a new material showing the controlled degradation and good molding properties, and to provide information on correlation of branched structure with biodegradability. A depsipeptide-lactide random copolymer having pendant hydroxy groups, poly[(Glc-Ser)-LA], was obtained by ring-opening copolymerization of L-lactide, LA, with a protected cyclodepsipeptide, cyclo[Glc-Ser(OBzl)], and consequent deprotection. The obtained copolymer was used as a macroinitiator for graft-polymerization of LA to give comb-type PLA. The obtained comb-type PLA showed a lower glass transition point, melting point, and apparent crystallinity than linear PLA. Furthermore, it was suggested that the degradation rate of comb-type PLA could be adjusted by controlling the molecular architecture such as molecular weight of main chain and/or side chain and number of graft chain.