A thermoplastic elastomer having a side chain having a moiety crosslinkable by hydrogen bond containing a carbonyl-containing group and a nitrogen-containing heterocycle, and another side chain having a covalently crosslinkable moiety, the thermoplastic elastomer being able to be crosslinked at the covalently crosslinkable moiety by at least one bond selected from the group consisting of amide, ester, lactone, urethane, ether, thiourethane, and thioether. The thermoplastic elastomer exhibits excellent mechanical strength without detracting from its excellent recycleability.