Conventional quenchers do not have quenching ability enough to suppress fluorescence emission of compounds having fluorescent property. Accordingly, it is an object of the present invention to provide a quencher capable of sufficiently quenching fluorescence of the compound having fluorescent property, including a xanthene-based dye.
The present invention relates to a quencher, or the like, comprising a compound represented by the following general formula (1):

[wherein R 5 each independently represent a halogen atom, an alkyl group, an alkoxy group, an alkylthio group, an amino group having a substituent or not having a substituent, a hydroxy group, an aryl group, an aryloxy group, or an arylalkyl group; R 6 represents a group having a polymerizable unsaturated group, a hydroxy group, or the like; Y 1 represents an oxygen atom, or the like; An - represents an anion; Ar 1 represents a specific ring structure; * and ** represent binding positions; Ar 2 represents a benzene ring, a naphthalene ring, or an anthracene ring; n 1 represents a specific integer;
and the following structure (1-10) in the general formula (1) is an asymmetric structure;

(wherein R 5 , Y 1 , Ar 1 , Ar 2 , n 1 , * and ** are the same as described above.).].