A conjugated diene-based polymer which includes a repeating unit (a) derived from a conjugated diene compound in a relative amount of 45 to 99 mass %; a repeating unit (b) derived from an aromatic vinyl compound in a relative amount of 0 to 40 mass; and a repeating unit (c) comprising a partial structure represented by formula (1) in a relative amount of 1 to 30 mass %, each relative amount based on the entire mass of all the repeating units; and a cross-linked product which is obtained by cross-linking of the polymer.

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