A method for producing a propylene-based block copolymer

Provides: a simple and high yield production of excellent polymerization activity and stereoregularity, rigidity, resistance to propylene-based copolymer having excellent impact resistance method. As follows: reacting a solid catalyst component comprising, a specific organoaluminum compound and a specific catalyst to external electron compound is contacted with propylene or propylene and upon contact with α- olefin, electron-donating compound further contacts for contacting the resultant product, thereby producing propylene block copolymer, the solid catalyst component containing titanium, magnesium, halogen and an internal electron donor compound.