To provide a piston that can suppress damage (surface roughening) from being generated on a top land surface.

A spark-ignition internal combustion engine provided with this piston 20, has a combustion chamber equipped with two intake valves 42, two exhaust valves 52, and an ignition plug 60, wherein the combustion chamber is defined by a cylinder head under surface as an in-cylinder ceiling 16, a cylinder block, and a crown face of the piston, and the ignition plug 60 is arranged at the almost center of the combustion chamber. The piston 20 has: valve recesses formed on the crown face of the piston; and protrusions 75 each formed between the two intake valve recesses 70F, 70R and generating squish flow in cooperation with the in-cylinder ceiling. The two intake valve recesses 70F, 70R are formed so that each amount overlapped with an outer circumferential side surface 22 of the piston, is different in a plan view.