A wet cleaning apparatus wherein rinse is carried out using ultrapure water as rinsing water by feeding the ultrapure water to a point of use within the apparatus through a pipeline, characterized in that a module (20) charged with a porous membrane holding therein a polymer chain having an anion-exchange group, a cation-exchange group or a chelating group is disposed at a midpoint in the pipeline. The rinsing water is preferably an ultrapure water containing hydrogen. The wet cleaning apparatus has an ability to remove impurities such as heavy metals and colloidal materials being contained in trace amounts in ultrapure water which is used as rinsing water in a cleaning process of a semiconductor, thereby inhibiting the deposition on a substrate of impurities such as fine particles and a heavy metal which adversely affect the characteristics of a device.
