PURPOSE: To produce a polyamide excellent in sliding properties without occurrence of phase separation by adding a hydrogenated poly-α-olefin, an isoparaffin, Fischer Tropsch wax and a mineral oil to a lactam and polymerizing it in the presence of an alkali catalyst and a cocatalyst.

CONSTITUTION: In polymerizing a lactam (e.g. -caprolactam) in the presence of an alkali catalyst (e.g. sodium hydride) in an amount of 0.05 to 10mol% based on the lactam and a cocatalyst (e.g. tolylene isocyanate) in an amount of 0.03 to 10mol% based on the lactam, (A) a hydrogenated poly-α-olefin, (B) an isoparaffin, (C) Fischer-Tropsch wax and (D) a mineral oil as the lubricants are added each in an amount of 1.0 to 6.0 pts.wt. and 4.5 to 12 pts.wt. in total respectively based on 100 pts.wt. lactam and the resultant mixture is thermally polymerized at 140°C. Thereby, the objective polyamide excellent in sliding properties can be obtained without occurrence of phase separation by a synergistic effect of the four components.