To form an engine in a compact size by attaching an attaching flange of an intake manifold to a cylinder head side surface of an inclining upper side of the engine, arranging a delivery pipe upward the flange, and arranging a pressure regulator between the delivery pipe and the flange.

An engine mounted in an engine room 6 is arranged by inclining a cylinder axis C1 around a crank axis C2, and an intake manifold 20 disposed continuously to a throttle body 18 of an intake device 16 is connected to a cylinder head 12 side surface of an inclining upper side of the engine 8 by an attaching flange 26. The intake manifold 20 is composed of a nearly square cylindrical surge tank 22 and a plurality of branch pipes 24 connected to the surge tank 22. A delivery pipe 42 is attached to the flange 26 through an attaching part, a pressure regulator 72 is arranged between the delivery pipe 42 and the flange 26 so as to prevent the pressure regulator 72 from protruding upward.