Polymer, method of producing polymer, and rubber composition

A rubber composition comprising a rubber component containing a polymer and carbon black and/or silica,

• the polymer comprising a repeating unit represented by Formula (1), a repeating unit represented by Formula (2), a repeating unit represented by Formula (3) and a repeating unit represented by Formula (4), wherein
• among all the repeating units, the proportion of a total of the repeating unit represented by Formula (1) is 5 mol % or greater;
• among all the repeating units, the proportion of the repeating unit represented by Formula (3) is 20 mol % or greater;
• and
• among all the repeating units, the proportion of the repeating unit represented by Formula (2) and the repeating unit represented by Formula (4) is from 1 to 80 mol %:
• where in Formula (1) and Formula (2), for R1 or R2, one represents an aromatic hydrocarbon group that may have at least one substituent, and the other represents a hydrogen atom, and
• in Formula (1) to Formula (4), RX and RY each represent a hydrogen atom, an alkyl group, or a halogen atom while at least one of RX and Ry represents a hydrogen atom.