A biodegradable resin composition comprising polylactic acid and nanosheeted layered titanic acid characterized in that the nonasheeted layered titanic acid is nanosheeted layered titanic acid obtained by a preparing process comprising the steps of: (1) treating layered titanate represented by the general formula: A.sub.xM.sub.y.quadrature..sub.zTi.sub.2-(y+z)O.sub.4 (1) [wherein A and M represent a different monovalent to trivalent metal, .quadrature. represents a part defective in Ti, x is a positive real number satisfying 0