An epoxy resin composition excellent in storage stability and curability is provided. Particularly, a compound of general formula (I) and an epoxy resin composition containing the compound as a curing agent are provided. In formula (I), R1 is a hydrocarbon group optionally containing a nitrogen atom and capable of forming a cyclic structure optionally having a substituent; R2 is a hydrogen atom, an alkyl group, or an aryl group or is taken together with R1 to form an unsaturated bond; R3 is a hydrogen atom, an alkyl group, or an aryl group; and X is a dicyanamide ion or a thiocyanate ion.