This polymer having a reactive silicon-containing group is represented by structural formula (1), and has good reactivity while having a monoalkoxysilyl group.




(In the formula, X represents a monovalent to trivalent organic group including a main chain backbone including a predetermined polymer such as a polyurethane, a poly(meth)acrylate, or a polysiloxane, R1 and R2 each independently represent an alkyl group or the like having 1-10 carbon atoms, Y represents O, S, or the like, A1 and A2 each represent a single bond, or a divalent linking group such as a divalent hydrocarbon group having 1-20 carbon atoms, and n represents a number of 1-3.)