To provide an inertia effect of intake air by lengthening a port length.

In this intake device of an inclined engine, an engine cylinder- shaft line is tilted to one side from the vertical direction in a view from a crankshaft, an intake-manifold fitting surface for a cylinder head is formed on an upper side of an engine cylinder-shaft line, and a surge tank disposed on the other side of the intake-manifold fitting surface is connected with the intake-manifold fitting surfaces with a plurality of inlet pipes. The center line of the inlet pipe is tilted to one side from the intake-manifold fitting surface and extended upward in an on-vehicle state, then, bent to the other side.