[Object] To provide a polypropylene resin composition for use in the formation of a microporous membrane having excellent heat resistance and low thermal shrinkage ratio.[Solution] A polypropylene resin composition for use in the formation of a microporous membrane according to the present invention comprises as an essential component a propylene homopolymer (A) that satisfies the following requirements (1) to (4) and (7): (1) the intrinsic viscosity [η] is 1 dl/g or more and less than 7 dl/g; (2) the mesopentad fraction ranges from 94.0% to 99.5%; (3) the integral elution volume during heating to 100° C. is 10% or less; (4) the melting point ranges from 153° C. to 167° C.; and (7) in an elution temperature-elution volume curve, the maximum peak has a peak top temperature in the range of 105° C. to 130° C. and a half-width of 7.0° C. or less.