PURPOSE: To obtain a simply producible polymer providing an adhesive composition having high adhesiveness to an inorganic material such as glass or metals and peel resistance without optionally requiring an additive such as a tackifier.

CONSTITUTION: This polymer has a hydroxyl group-containing functional group which is bonded at least one hydroxyl group at the end of a conjugated diene/ vinyl aromatic hydrocarbon block copolymer and to which Si containing at least one alkoxy group is bonded. The polymer, for example, comprises one or more molecular structures of the formula [P is a copolymer; R1 is H or a 1-10C alkylene; R2 is a 1-20C aliphatic or alicyclic hydrocarbon; R3 is H or a (substituted) methylene; R4 is a 1-20C aliphatic hydrocarbon; R5 and R6 are each a 1-20C aliphatic, alicyclic or aromatic hydrocarbon; (x) and (y) are each 1-3; (z) is 0-2; x+y+z=2-4; (n) is 0 or 1]. The polymer is preferably obtained by reacting a silane compound composed of β-(3,4-epoxycyclohexyl)ethyl- trimethoxysilane with end lithium of a block copolymer.