To obtain a (meth)acrylic acid ester-based polymer that is crosslinked with moisture to provide a cured material having excellent durability and a curable composition comprising the polymer, especially a (meth)acrylic acid ester-based polymer having excellent storage stability and quick-curing properties and a curable composition.

The (meth)acrylic acid ester-based polymer containing a crosslinkable, hydrolyzable silyl group on the end is a (meth)acrylic acid ester-based polymer in which the crosslinkable, hydrolyzable silyl group is at least one selected from a triethoxysilyl group, a diethoxysilyl group and a dimethoxysilyl group and which contains 1.2-4.0 of the hydrolyzable silyl group on the average of number in one molecule.