To provide a hardly colored curable composition having an excellent storage stability while maintaining fast curing properties.A curable composition which comprises a polymer (P) having a polyoxyalkylene chain and a group of the following formula (1) and a compound (S) having a mercapto group and a group of the following formula (2), and which contains from 0.01 to 0.50 part by mass of the compound (S) per 100 parts by mass of the polymer (P): —Si(—X1)3  (1) —Si(—X2)m(—Y2)3-m  (2) wherein symbols have the following meanings: X1 and X2: each independently a C1-6 alkoxy group, Y2: a C1-6 alkyl group, and m: 1, 2 or 3.