A biaxially stretched polypropylene film of the present invention has high stiffness in the film longitudinal direction and can be manufactured by a conventional longitudinal-transverse sequential biaxial stretching method, since the biaxially stretched polypropylene film comprises a polypropylene which comprises a polypropylene having controlled specific values of a melt strength (MS) and a melt flow rate (MFR) at 230.degree. C. or consists of a polypropylene having controlled specific values of a melt strength (MS) and a melt flow rate (MFR) at 230.degree. C. and/or a Trouton ratio of the polypropylene is controlled at a specific value, moreover, the biaxially stretched polypropylene film contains regulated longitudinal fibrils.