<p>A diesel engine in which a lubrication oil on the wall surface of the cylinder liner is prevented from being burned and diluted, and a smoke resulting from the local lack of air in the combustion chamber is also prevented from being generated. The diesel engine comprises a group injection hole nozzle (20) and a piston (110). A step (115) having a height gradually increased toward the radial outer circumference of the piston is formed over the entire circumference of the top surface (111) of the piston. Furthermore, a tilted part (115b) is formed as the step surface of the step (115).</p>
