A honeycomb structure includes center and peripheral regions. The center region has a smaller similarity shape in relation to a peripheral shape of the honeycomb structure in a cross section perpendicular to the longitudinal direction. The peripheral region is located outside the smaller similarity shape. Zeolite ion-exchanged with at least one of Cu, Mn, Ag, and V is present at a first weight ratio and a second weight ratio in the center region and the peripheral region, respectively, relative to a total weight of the zeolite. The second weight ratio is larger than the first weight ratio. Zeolite ion-exchanged with at least one of Fe, Ti, and Co is present at a third weight ratio and a fourth weight ratio in the center region and the peripheral region, respectively, relative to a total weight of the zeolite. The third weight ratio is larger than the fourth weight ratio.