Enhancer reagent for a chemiluminescence reaction and compound

An enhancer reagent for a chemiluminescence reaction, comprising:

• a compound represented by Formula (1),
• in the formula, X represents a pyridyl group which may be substituted with one or more groups selected from the group consisting of an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an alkoxycarbonyl group, a cycloalkoxycarbonyl group, an amino group, an acylamino group, a silyl group, a silyloxy group, a hydroxyl group, a cyano group, a nitro group, a halogen atom, a carboxy group, a sulfo group, a phosphonyl group, a phosphoryl group, a boronic acid group, and a sulfanyl group.