A clathrate compound obtained by mixing an imidazole compound (A) and a polyhydric phenol compound (B), wherein the clathrate compound has an average particle size (X) of 7 μm or less, and a maximum particle size (Y) of 40 μm or less. The imidazole compound (A) is preferably at least one selected from compounds represented by the following formula (1), where R1, R2, R3, and R4 each independently represent a hydrogen atom, an alkyl group that has 1 to 20 carbon atoms and may have a substituent, or an aryl group that has 6 to 20 carbon atoms and may have a substituent, and the substituent is at least one selected from a halogen atom, a hydroxy group, and a nitrile group.