A thermosetting composition combining excellent storage stability with cold curability and comprising (A) a polyisocyanate compound or/and an active-isocyanate-terminated urethane prepolymer prepared by the reaction of a polyol component with an excessive polyisocyanate compound and (B) a solid amine having a melting point of 50 DEG C or above, a median particle diameter of 20 mu m or less and active surface amino groups covered by a fine powder having a median particle diameter of 2 mu m or less and active surface amino groups covered by a fine powder having a median particle diameter of 2 mu m or less, the weight ratio of the amine to the powder being 1/0.001-0.5.
