To obtain a piston for internal combustion engine having stable strength without thinning the thickness of the piston near a supporting body by inclining the center line of the supporting body to the outer peripheral side of the piston and positioning the tip end side connecting with a soluble core to near the outer periphery of the piston.

The supporting body 6 is formed as truncated conical table state and this center line C is inclined to the outer peripheral side of the piston so as to position this top end part contacting with the soluble core 4 to the outer peripheral side of the piston. On the tip end part of the supporting body 6 contacting with the soluble core 4, a curved recessed surface 7 is formed so as to match to the outer peripheral shape of the soluble core 4, and the soluble core 4 can stably be held with this recessed surface 7. Further, on the tip end part of the supporting body 6, a restrained pin 8 is arranged and the positioning of the soluble core 4 is easily executed by engaging this restrained pin 8 with a restrained hole 9 formed in the soluble core 4.