An internal combustion engine includes a fuel injection nozzle that is arranged at the center of an upper surface of a combustion chamber with an injection port thereof exposed in the combustion chamber, and a piston arranged in a cylinder. On a top surface of the piston, a flow guide passage is provided which extends from an inlet exposed on the side of a wall of a bore of the cylinder to an outlet exposed on the side of a center of the bore. The flow guide passage preferably includes a flow guide plate having a ring shape, and a strut that fixes the flow guide plate to the top surface of the piston in such a manner that a clearance extending from an outer edge to an inner edge of the flow guide plate is formed between the flow guide plate and the top surface of the piston.