NOVELTY - A curable composition comprises 100 parts mass polymer (A), and 0.4-2 parts mass two or more types of compounds (B) which produce trimethylsilanol by hydrolysis. Polymer (A) is obtained by introducing a reactive silicon group into a precursor polymer (A'). Polymer (A) has a functional group which can introduce a reactive silicon group into all the principal chain terminals. The functional group is group having active hydrogen, and/or unsaturated group. Polymer (A) has an alkylene-oxide monomeric unit in the principal chain.    USE - Curable composition. Uses include but are not limited to adhesive agent, elastic sealing compound sealant used in construction, sealing material of multilayer glass, sealing agent used for rustproofing and waterproofing of glass edges, solar cell backside sealing agents, electrical insulation coating materials of electric wires and cables, and construction sealing materials for outdoor applications requiring expansion-contraction-proof fatigability.    ADVANTAGE - The curable composition has excellent hardenability, and provides cured material having excellent elongation, crack resistance, and durability, and no surface stickiness.    DETAILED DESCRIPTION - A curable composition comprises 100 parts mass polymer (A), and 0.4-2 parts mass two or more types of compounds (B) which produce trimethylsilanol by hydrolysis. Polymer (A) is obtained by introducing a reactive silicon group of formula: -Si(X1)2R1 into a precursor polymer (A'). Polymer (A) has a functional group which can introduce a reactive silicon group into all the principal chain terminals. The functional group is group having active hydrogen, and/or unsaturated group, and the average functional group number is 2-3 at the principal chain terminal. Polymer (A) has an alkylene-oxide monomeric unit in the principal chain, a molecular weight per functional group of 7000-20000, and a molecular weight distribution of 1.01-1.4.    R1=optionally substituted 1-20C monovalent organic group (except hydrolyzable group);and    X1=hydroxy or hydrolyzable group.