A honeycomb structural body includes a honeycomb unit having a plurality of through holes defined by cell walls and arranged in a longitudinal direction of the honeycomb unit. The honeycomb unit includes an inorganic binder, a first zeolite, and second zeolite. The first zeolite includes at least one of a β type zeolite and a ZSM-5 type zeolite, and primary particles having an average particle diameter of approximately 0.01 μm or more and approximately 0.1 μm or less. The second zeolite includes a phosphate group zeolite and primary particles having an average particle diameter of approximately 0.5 μm or more and approximately 5 μm or less. A ratio between a mass of the first zeolite and a total mass of the first and second zeolites is approximately 0.1 or more and approximately 0.5 or less.