PURPOSE: To produce a cylinder for a plastic molding machine which lasts long and is economical by forming a plating-layer on the inside circumferential surface of the cylinder then heat treating the cylinder in a specific temp. range to effect diffusion bonding of the base material of the cylinder and the plating layer.

CONSTITUTION: A plating layer 3 consisting of a plating material such as electroless Ni-P or electroless composite Ni-P formed by incorporating hard particles of SiC, WC, TiC, etc. in a base material of electroless Ni-P is formed to about 80μm thickness on the inside circumferential surface of a cylinder 2 formed of a Cr-Mo steel, etc. The cylinder 2 is then heated and held for about 5hr 550W750°C to form a diffusion bond phase between the base material of the cylinder 2 and the plating layer 3. The peeling and dislodging of the layer 3 owing to corrosion are thus prevented, and a cylinder 1 for a plastic molding machine which is highly resistant to peeling and wear, is usable for working of a resin such as "Teflon" resin having high corrosiveness, long life and is economical, is obtd.