A honeycomb structure excellent in thermal dispersibility upon heating and being protected from damage due to thermal stress, and an efficient method for manufacturing the honeycomb structure. The structure is provided with porous partition walls, functioning as a filtration layer, through which exhaust gas flowing into the cells can flow out, and plugging portions. Additional plugging portions are further disposed in the open end portions to which the plugging portions are not disposed (unplugged open end portions) not so as to plug unplugged open end portions. Each cross-sectional shape of additional plugging portions in a direction perpendicular to the axial direction forms a predetermined pattern shape as a whole, and a barycenter of the pattern shape is located in almost the center of a cross section of a flow of the exhaust gas in a direction perpendicular to the axial direction.