To provide a propylene-based polymer composition which not only excels in the rigidity in the film flow direction and the film strength but also excels in molding processability, and a biaxially oriented polypropylene film which has harmoniously improved film rigidity and film strength.

The propylene-based polymer composition comprises 100 pts.wt. propylene-based polymer having an isotactic triad fraction of ≥97% as the (A-1) characteristic, a ratio of positionally irregular units based on the 2,1-insertion of the propylene monomer of 0-0.4% and a ratio of positionally irregular units based on the 1,3-insertion of the propylene monomer of 0.06-0.4% as the (A-2) characteristic, and an MFR of 0.5-10 and, simultaneously, the MFR and a memory effect (ME) measured at 190°C which meet the formula: ME≥-0.26×log MFR+1.55 and 0.01-1 pt.wt. antioxidant as the (A-3) characteristic.