A direct fuel injection-type spark-ignition internal combustion engine is disclosed. The engine comprises a cavity formed on the top surface of the piston, a spark plug facing the inside of said cavity, and a fuel injection valve for injecting fuel into the cavity in nearly the shape of a fan having a relative small thickness. The cavity has a bottom wall onto which the injected fuel impinges initially and a side wall facing to the fuel injection valve. The side wall has a deflection portion which is nearly the shape of a linear line and a circular arc portion which connects the deflection portion and the bottom wall smoothly in a vertical section. An angle of the deflection portion with the bottom wall is in a range from 50 to 80 degrees. A radius of the circular arc portion is in a range from 5 to 15 mm.