Polymerizable composition, cycloolefin-based polymer, and metal/resin composite

A polymerizable composition comprising:

• at least one of a cycloolefin-based monomer (α) represented by General Formula (I) and a cycloolefin-based monomer (β) represented by General Formula (II), a silane coupling agent having at least one hydrocarbon group having a norbornene structure, and a metathesis polymerization catalyst:
• where R1 represents a substituent selected from the group consisting of C1 to C10 hydrocarbon groups, halogen atoms, and C1 to C10 hydrocarbon groups substituted by a halogen atom:
• m represents an integer of 0 or more and 6n+6 or less;
• when m is 1 or more, R1 can be bonded to any bonding position;
• when m is 2 or more, R1s may be the same or different;
• and n represents an integer of 1 to 3;
• where h represents an integer of 1 to 3, i and j each independently represent an integer of 0 to 4, and k represents an integer of 1 to 4.