To provide a continuous annealing apparatus for wire rod, in which the washing effect of the wire rod can be improved in a cooling zone containing circulating water.

The lower side of one electrode sheave in the upper and the lower electrode sheaves for winding the wire rod, is arranged in a vessel filled with the circulating water, and also, ultrasonic generating elements at the inlet side and the outlet side of the wire rod is arranged in the vessel in a constitution having troughs filled with the circulating water at wire rod passingthrough portions between the upper and the lower electrode sheaves, and uniform ultrasonic vibration is given to the wire rod and/or the circulating water from this ultrasonic generating elements to improve the surface washing effect on the wire rod. The washing effect can further be improved by mixing the circulating water, with isopropyl alcohol.