Disclosed is a conjugated diene polymer comprising a conjugated diene as a monomeric unit. The conjugated diene polymer is obtained by a polymerization reaction in a reaction solution comprising a conjugated diene, at least one compound selected from the group consisting of limonene, terpinene, and terpinolene, and an organoalkali metal compound as a polymerization initiator. Mz/Mn is 1.7 or more and 4.0 or less, when Mz is a Z-average molecular weight of the conjugated diene polymer, Mn is a number average molecular weight of the conjugated diene polymer, and the Z-average molecular weight and the number average molecular weight are values in terms of polystyrene by gel permeation chromatography.