A detergent for a contact lens comprising 40 to 80% by weight of fine particles of a water-soluble compound which has a salt value of at most 0.65 and a solubility in water of 3 to 30 at 30.degree. C. and at most 40 at 60.degree. C., with the product of the salt value and the solubility at 30.degree. C. being at most 10, and 100% of which passes a JIS standard sieve of a nominal size of 75 .mu.m, and 60 to 20% by weight of a pasting agent containing as a major component an aqueous dispersion of a gel composed of an acrylic acid compound having a recurring unit represented by the general formula (I): ##STR1## wherein R.sub.1 represents hydrogen atom and/or methyl group, R.sub.2 represents at least one member selected from hydrogen atom, sodium atom, potassium atom, lithium atom, NH.sub.4 group, a residue of a saturated polyhydric alcohol having 2 to 4 carbon atoms and an alkyl group having 1 to 32 carbon atoms and having a crosslinking site in its recurring unit, and a polyhydric alcohol, and a method for washing a contact lens using the same are disclosed.