Quenchers of the related art do not have a quenching ability high enough to sufficiently inhibit the emission of fluorescence from fluorescence compounds. Therefore, the present invention aims to provide a quencher which can sufficiently quench the fluorescence from fluorescent compounds including xanthene-based dyes. The present invention relates to a quencher formed of a compound represented by the following general formula (1), and the like. (In the formula, n1 pieces of R5 each independently represent a group having a polymerizable unsaturated group, an amino group having a substituent, or the like, R6 represents a group having a polymerizable unsaturated group, a hydroxy group, or the like, An− represents an anion, Ar1 represents a specific ring structure, * and ** each represent a position of bonding to the specific ring structure, Ar2 represents a benzene ring or the like, in a case where Ar2 is the benzene ring, n1 represents an integer of 0 to 4, and R32 and R33 each independently represent an alkyl group or an aryl group.).