A polymer composition comprising: a conjugated diene-based polymer that is a reaction product between a polymer having an active polymerization end, the polymer being obtained by polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, in the presence of an alkali metal compound or an alkaline earth metal compound, and a compound represented by any one of the following general formulae to; and conjugated diene-based polymer particles: in the formula, A 2 represents a monovalent group bonded to L 2 via an imino group, an amide group, a (thio)carbonyl group, a (thio)carbonyloxy group, a sulfide, or a polysulfide, or represents a protected primary amino group, a protected secondary amino group, a tertiary amino group, a nitrile group, a pyridyl group, a (thio)epoxy group, a (thio)isocyanate group, a (thio)formyl group, a (thio)carboxylic acid ester, a metal salt of a (thio)carboxylic acid ester, a carboxylic halide, an imidazolyl group, or a group represented by the following formula, L 2 and L 3 each independently represent a single bond or a hydrocarbylene group having 1 to 20 carbon atoms, R 3 and R 4 each independently represent a hydrocarbyl group having 1 to 4 carbon atoms, n2 represents from 0 to 3, and m1 represents 0 or 1; in the formula, L 3, R 3, R 4, and n2 are the same as in the formula, and "*" represents a site to be bonded to L 2; in the formula, A 3 s each independently represent an imino group, an amide group, a (thio)carbonyl group, a (thio)carbonyloxy group, a secondary amino group, or a tertiary amino group, Z represents a nitrogen atom-containing or -free t-valent group having 1 to 20 carbon atoms, L 4 represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms, L 5 represents a hydrocarbylene group having 1 to 20 carbon atoms, R 5 and R 6 each independently represent a hydrocarbyl group having 1 to 4 carbon atoms, n3 represents 0 or 1, and "t" represents 2 or 3; and in the formula, R 7 and R 8 each independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R 9 represents a hydrocarbyl group having 1 to 20 carbon atoms, or a substituted alkyl group having 1 to 20 carbon atoms, at least one of a hydrogen atom or -CH 2 - of the alkyl group being substituted with a group containing at least one kind of element selected from the group consisting of: silicon; nitrogen; phosphorus; oxygen; and sulfur, or represents an aromatic group having 6 to 20 carbon atoms, the aromatic group containing at least one kind of element selected from the group consisting of: nitrogen; phosphorus; oxygen; and sulfur, R 10 represents an alkanediyl group having 1 to 20 carbon atoms, and n4 represents 1 or 2. a conjugated diene-based polymer that is a reaction product between a polymer having an active polymerization end, the polymer being obtained by polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, in the presence of an alkali metal compound or an alkaline earth metal compound, and a compound represented by any one of the following general formulae to; and conjugated diene-based polymer particles: in the formula, A 2 represents a monovalent group bonded to L 2 via an imino group, an amide group, a (thio)carbonyl group, a (thio)carbonyloxy group, a sulfide, or a polysulfide, or represents a protected primary amino group, a protected secondary amino group, a tertiary amino group, a nitrile group, a pyridyl group, a (thio)epoxy group, a (thio)isocyanate group, a (thio)formyl group, a (thio)carboxylic acid ester, a metal salt of a (thio)carboxylic acid ester, a carboxylic halide, an imidazolyl group, or a group represented by the following formula, L 2 and L 3 each independently represent a single bond or a hydrocarbylene group having 1 to 20 carbon atoms, R 3 and R 4 each independently represent a hydrocarbyl group having 1 to 4 carbon atoms, n2 represents from 0 to 3, and m1 represents 0 or 1; in the formula, L 3, R 3, R 4, and n2 are the same as in the formula, and "*" represents a site to be bonded to L 2; in the formula, A 3 s each independently represent an imino group, an amide group, a (thio)carbonyl group, a (thio)carbonyloxy group, a secondary amino group, or a tertiary amino group, Z represents a nitrogen atom-containing or -free t-valent group having 1 to 20 carbon atoms, L 4 represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms, L 5 represents a hydrocarbylene group having 1 to 20 carbon atoms, R 5 and R 6 each independently represent a hydrocarbyl group having 1 to 4 carbon atoms, n3 represents 0 or 1, and "t" represents 2 or 3; and in the formula, R 7 and R 8 each independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R 9 represents a hydrocarbyl group having 1 to 20 carbon atoms, or a substituted alkyl group having 1 to 20 carbon atoms, at least one of a hydrogen atom or -CH 2 - of the alkyl group being substituted with a group containing at least one kind of element selected from the group consisting of: silicon; nitrogen; phosphorus; oxygen; and sulfur, or represents an aromatic group having 6 to 20 carbon atoms, the aromatic group containing at least one kind of element selected from the group consisting of: nitrogen; phosphorus; oxygen; and sulfur, R 10 represents an alkanediyl group having 1 to 20 carbon atoms, and n4 represents 1 or 2.