PURPOSE: To produce a lightweight piston of thin thickness which is a thin walled hollow pipe by forming a fiber reinforced metallic layer in the thin walled hollow pipe packed with fibers with a high pressure casting device then removing the stuck metal on the outside wall of the hollow pipe.

CONSTITUTION: Reinforcing fibers 2 which are oriented in the longitudinal axial line direction of a thin walled hollow pipe 1 are inserted into said pie and the pipe is inserted into the high pressure casting chamber 4 of a high pressure casting device 3. Thereafter, molten metal 5 is charged into the chamber 4, and is pressurized with a piston 6. The metal 5 infiltrates among the fibers 2 and solidifies, thus forming a fiber reinforced metallic layer 7 of which the matrix is metal in the pipe 1. The pipe 1 is removed, and the metal 5 solidified on the outside circumferential wall surface is removed by machining, whereby the piston formed with the layer 7 in the inside is formed.