PURPOSE: To strip a water-soluble photoresist, by using hexamethyl-phosphoramide.

CONSTITUTION: A photoresist plate with an image formed is immersed in an aqueous solution containing hexamethylphosphoramide represented by the chemical formula (I) and further, when needed, periodate and a surfactant, and treated in 40W90°C temperature range. Hexamethylphosphoramide is contained in 1W10wt% range. The action is smaller below this range, but it is not so much raised above this range. The periodate and the surfactant enhance wettability and diffusibility, shorten the treatment time, and reduce an amount of hexamethylphosphoramide to be used. The photoresist may be removed by coating this solution and rubbing it with a brush, but the immersion method is much easier. This solution does not corrode a metal, and its operation is out of danger.