There is disclosed a honeycomb structure which has an excellent collecting performance of a particulate matter and in which a pressure loss during flowing of a fluid through the honeycomb structure is low. The honeycomb structure includes a honeycomb base material having porous partition walls with which a plurality of cells are formed to become through channels of a fluid, a value of a ratio of an average open frontal area diameter of pores which are open in the surfaces of the partition walls to an average pore diameter of the pores formed in the partition walls is from 0.05 to 0.45, the partition walls have a single layer structure, and preferably, an open frontal area diameter of each of the pores which are open in the surfaces of the partition walls is from 0.5 to 10 μm.