Abstract: A steel wire heat treatment apparatus is entirely free from the disadvantage of oxidation of the steel wire during treatment. The apparatus includes a heating furnace with a plurality of heating pipes passing, and through which wire rods being heated are passed, and a tempering oil tank provided at a wire rod outlet side of the heating furnace. An end portion of the wire rod outlet side of each heating pipe communicates with the tempering oil tank. An oil-drain pipe is arranged below each heating pipe in such a fashion that one end thereof communicates with the heating pipe and the other end thereof is maintained immersed in oil within an oil-drain tank.