HONEYCOMB STRUCTURE

To provide a honeycomb structure capable of relaxing stress concentration occurring in the vicinity of a boundary wall, and excellent in thermal shock resistance.SOLUTION: The honeycomb structure is provided with a columnar honeycomb structure part 4 having a porous boundary wall 1 for partitioning a plurality of cells 2 as a flow path of a fluid extending from an inlet end face to an outlet end face, and an outer peripheral wall disposed so as to surround the outer periphery of the boundary wall 1. The honeycomb structure part 4 has an outer peripheral cell structure 16, a central cell structure 15, and a boundary wall 8 disposed at a boundary between the outer peripheral cell structure 16 and the central cell structure 15 in a face orthogonal to an extending direction of the cells 2 of the honeycomb structure part 4, and 5% or more and 50% or less of imperfect cells 2y in all of imperfect cells 2y of the central cell structure 15 communicate with imperfect cells 2y of the outer peripheral cell structure 16 each other.SELECTED DRAWING: Figure 4 【課題】境界壁の近傍に発生する応力集中を緩和することができ、耐熱衝撃性に優れたハニカム構造体を提供する。【解決手段】流入端面から流出端面まで延びる流体の流路となる複数のセル２を区画形成する多孔質の隔壁１、及び隔壁１の外周を囲繞するように配設された外周壁を有する、柱状のハニカム構造部４を備え、ハニカム構造部４は、ハニカム構造部４のセル２の延びる方向に直交する面において、外周セル構造１６と、中央セル構造１５と、外周セル構造１６と中央セル構造１５との境界に配設された境界壁８と、を有し、中央セル構造１５の不完全セル２ｙの全個数のうちの５％以上、５０％未満の不完全セル２ｙが、外周セル構造１６の不完全セル２ｙと互いに連通している。【選択図】図４