Foamed particles of modified polypropylene resin and method of preparing same

A foamed, non-crosslinked resin particle having a bulk density of not greater than 0.045 g/cm.sup.3 and an average cell diameter of at least 200 .mu.m, said non-crosslinked resin comprising a polypropylene resin to which a vinyl comonomer is graft-polymerized in such an amount that the weight ratio of said polypropylene resin to said grated polymer of said vinyl comonomer is in the range of 97:3 to 65:35, wherein said foamed, non-crosslinked resin particle has a melting point of at least 125.degree. and a DSC curve by differential scanning calorimetry that includes at least two endothermic Peaks and wherein the highest of the at least two endothermic peaks has an area corresponding to the calorific value of 2-25 J/g when the modified polypropylene resin has a melting point of 150.degree. C. or less or 5-40 J/g when the modified polypropylene resin has a melting point of more than 150.degree. C.