To provide a cooling structure of a piston for an internal combustion engine excellent in productivity with a simple shape cooling channel and capable of efficiently cooling a crown part.

In this cooling structure of the piston for the internal combustion engine, an oil inlet passage 15 introducing cooling oil injected from an injection nozzle 31 to the cooling channel 10 communicates to the annular cooling channel 10 in the crown part 2, and the cooling oil introduced from the oil inlet passage 15 is divided in two directions by an inner surface 10b of the cooling channel 10 opposing to the oil inlet passage 15. The oil inlet passage 10 is inclined to a circumference direction of the inner surface 10b with including an inclination direction component. The cooling oil introduced from the oil inlet passage 15 is controlled and divided into two direction flows predetermined by the inner surface 10b and the crown part 2 can be efficiently cooled.