A dual-injector fuel injection engine comprising: a cylinder block formed with a plurality of cylinder holes each of which forms a cylinder with an axial direction which is perpendicular to a crankshaft; a cylinder head attached on said cylinder block, said cylinder head forming an upper wall of a combustion chamber in each cylinder; an intake port formed in said cylinder head for each cylinder, said intake port extending from said combustion chamber in the cylinder and serving as an intake passage for each cylinder; an intake manifold attached to said cylinder head, said intake manifold including a plurality of intake passages (53, 54), each of which communicates with said corresponding intake port; a surge tank provided upstream of said intake manifold and shared by said plurality of cylinders; an in-cylinder injector provided to each cylinder to inject fuel directly into said combustion chamber; an intake pipe injector provided to each cylinder to inject the fuel into said intake port; a first delivery pipe connected to all said in-cylinder injectors to supply the fuel thereto; and a second delivery pipe connected to all said intake pipe injectors to supply the fuel thereto, characterized in that, said intake port includes an intake pipe connection portion which extends from a downstream end thereof obliquely upward with respect to an axis of said corresponding cylinder, wherein said intake pipe connection portion forms a horizontal flat surface at an upper end thereof, downstream ends of said intake manifold are connected to said horizontal flat surface of said corresponding intake pipe connection portion, said in-cylinder injector and said first delivery pipe are attached to said cylinder head, wherein said in-cylinder injector and said first delivery pipe are positioned below said intake pipe connection portion when seen from the axial direction of said crankshaft, said intake pipe injector and said second delivery pipe are supported above said intake port and positioned on a side opposite to said in-cylinder injector across said intake port, when seen from the axial direction of said crankshaft, and close to a mating surface where said intake pipe connection portion and each of downstream ends of said intake manifold mate, and an attaching seat to which said intake pipe injector is attached is formed on said intake manifold close to said mating surface. a cylinder block formed with a plurality of cylinder holes each of which forms a cylinder with an axial direction which is perpendicular to a crankshaft; a cylinder head attached on said cylinder block, said cylinder head forming an upper wall of a combustion chamber in each cylinder; an intake port formed in said cylinder head for each cylinder, said intake port extending from said combustion chamber in the cylinder and serving as an intake passage for each cylinder; an intake manifold attached to said cylinder head, said intake manifold including a plurality of intake passages (53, 54), each of which communicates with said corresponding intake port; a surge tank provided upstream of said intake manifold and shared by said plurality of cylinders; an in-cylinder injector provided to each cylinder to inject fuel directly into said combustion chamber; an intake pipe injector provided to each cylinder to inject the fuel into said intake port; a first delivery pipe connected to all said in-cylinder injectors to supply the fuel thereto; and a second delivery pipe connected to all said intake pipe injectors to supply the fuel thereto, characterized in that, said intake port includes an intake pipe connection portion which extends from a downstream end thereof obliquely upward with respect to an axis of said corresponding cylinder, wherein said intake pipe connection portion forms a horizontal flat surface at an upper end thereof, downstream ends of said intake manifold are connected to said horizontal flat surface of said corresponding intake pipe connection portion, said in-cylinder injector and said first delivery pipe are attached to said cylinder head, wherein said in-cylinder injector and said first delivery pipe are positioned below said intake pipe connection portion when seen from the axial direction of said crankshaft, said intake pipe injector and said second delivery pipe are supported above said intake port and positioned on a side opposite to said in-cylinder injector across said intake port, when seen from the axial direction of said crankshaft, and close to a mating surface where said intake pipe connection portion and each of downstream ends of said intake manifold mate, and an attaching seat to which said intake pipe injector is attached is formed on said intake manifold close to said mating surface.