Polypropylene based resins and compositions comprising the resin having extremely high stiffness, heat resistance and impact strength, with these properties being well-balanced, are provided. The polypropylene based resins are characterized by comprising:(1) a propylene polymer having a content of alpha-olefin other than propylene of not more than 4 mole percent, and the following properties (2), (3) and (4):(2) a pentad fraction (mmmm fraction) measured by .sup.13 C-NMR of not less than 96.0 percent,(3) a main elution fraction peak position of not less than 118.0.degree. C. and a peak half value width of less than 4.0, these values being measured by the temperature raising separation method, and(4) an intrinsic viscosity of not less than 0.5 dl/g, but not more than 5.0 dl/g; and,(5) a rubber content measured by pulse NMR of more than 25 percent.