PURPOSE: To obtain a polyamide monofilament suitable for a drier canvas and a brush for washing an iron and steel, capable of maintaining a strength and a moist heat resistance together with a good wear resistance against metals.

CONSTITUTION: A copolyamide consisting of 60-70mole% of a structural unit as a repeating unit composing a copolymer, expressed by the formula I (R is a 6C linear aliphatic hydrocarbon), 20-30mole% of a structural unit expressed by the formula II (R is the same as above), and 15mole% of a structural unit expressed by the formula III (R is the same as above), is prepared. A polymer composition is obtained by combining 2-15% of an ionomer resin obtained by crosslinking of an ethylene-methacrylic acid copolymer with Zn ion, to the above copolyamide, and is melt spun and drawn to obtain a polyamide monofilament.