A ceramic honeycomb structure having a large number of flow paths defined by porous cell walls having porosity of 45-68% and an average pore size of 15-35 μm, the volume of pores having diameters of more than 50 μm being more than 10% and 25% or less of the total pore volume, the volume of pores having diameters of 100 μm or more being 1-8% of the total pore volume, the volume of pores having diameters of less than 10 μm being 3-10% of the total pore volume, and the pores having a pore size distribution deviation σ [=log(D20)−log(D80)] of 0.45 or less, wherein D20 represents a pore size (μm) at a pore volume corresponding to 20% of the total pore volume, and D80 represents a pore size (μm) at a pore volume corresponding to 80% of the total pore volume, in a curve showing the relation between a pore size and a cumulative pore volume obtained by accumulating a pore volume from the maximum pore size to a particular pore size, and D80