Abstract: A thermoplastic resin composition prepared by adding, to a vinyl chloride resin composition or its homologous series resin composition, a glycerin ester represented by the following formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 represent each an acyl group or a hydrogen atom, said acyl group comprises one having 2 carbon atoms and one consisting mainly of those having 10 to 14 carbon atoms, the acyl group having 2 carbon atoms is present in an amount, on the average, of up to 2 mol per mol of glycerin, the acyl group consisting mainly of those having 10 to 14 carbon atoms are present in an amount, on the average, of at least 0.9 mol per mol of glycerin and the total amount of the acyl groups is, on the average, 2.7 to 3.0 mol per mole of glycerin.