Fluorescent labeling agent and fluorescent dye

A fluorescent labeling agent comprising:

• a fluorescent dye containing a phthalocyanine dye represented by the following general formula (2),
• here, X1-X16 each independently represent —Z—R1—R2—R3, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted heterocyclic group, -AB, —SO3M5, or —COOM6,
• in the -AB, A represents a Group 16 element, B represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted heterocyclic group,
• the M5 and M6 each independently represent a monovalent cation, or
• in the X1-X16, adjacent substituents may be linked to each other to form a ring,
• X17 represents —Z—R1—R2—R3, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, —OP(═O)X18X19, —OC(═O)X20, —OS(═O)2X21, or —OSiX22X23X24,
• the X18 and X19 each independently represent a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted heterocyclic group,
• the X20 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group,
• the X21 represents a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group,
• the X22-X24 each independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group,
• Y represents a trivalent to pentavalent metal atom, and k is an integer, in a case where Y is a trivalent metal atom, k is 1, and, in a case where Y is a tetravalent or pentavalent metal atom, k is 2,
• here, at least one of X1-X17 is —Z—R1—R2—R3,
• Z represents a direct bond, a substituted or unsubstituted alkylene group, or a substituted or unsubstituted arylene group,
• R1 represents —OP(═O)R4—, —OC(═O)—, —OS(═O)2—, —C(═O)—, or —C(═O)NH—,
• R2 represents a group selected from the group consisting of unsubstituted alkylene groups, substituted or unsubstituted arylene groups, and substituted or unsubstituted heterocyclic groups, or represents a group provided by combining these groups,
• R3 represents —COOM1, —NR7R8, —OM2, or —P(═O)(OM3)OM4,
• the R4 represents a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted heterocyclic group,
• the R7-R8 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and
• the M1, M2, M3, and M4 each independently represent a hydrogen atom or a monovalent cation.