Production method for aromatic vinyl-diene copolymer and production method for rubber composition

A method of producing an aromatic vinyl-diene copolymer, the aromatic vinyl-diene copolymer being a copolymer of an aromatic vinyl and a diene,

• the aromatic vinyl-diene copolymer having a content of repeating units derived from an aromatic vinyl in an amount of 18 mass % or greater, among repeating units derived from a diene, a proportion of a vinyl structure of 8 mol % or less, a proportion of a 1,4-trans structure of 60 mol % or less, and a proportion of a 1,4-cis structure from 40 to 95 mol %, and
• the aromatic vinyl-diene copolymer having a terminal that is modified with at least one electrophile selected from the group consisting of titanium halide, tin halide, cyclic silazane, alkoxysilane, epoxide, amine, ketone, and a compound represented by Formula (N) below,
• the method of producing the aromatic vinyl-diene copolymer comprising:
• copolymerizing a monomer containing an aromatic vinyl and a diene using an initiator, the initiator being prepared with an organolithium compound, an alkylaluminum, a metal alcoholate, and at least one polar compound comprising water;
• and
• then terminating the polymerization using the electrophile:
• where in Formula (N), R1 represents a hydrogen atom or an alkyl group, and R2 represents an alkylene group.