Thermal shock resistant ceramic honeycomb structures in which the shape of the vertical cross-section of the honeycomb structure is elliptical, and the shape of the channels is quadrilateral, one group of the partitions of the channels being inclined against the long diameter direction of the ellipse-shaped honeycomb structure and another group of the partitions of the channels being parallel to or inclined against the short diameter direction, the two groups of partitions are being crossed to form the quadrilateral channels.