The present invention provides a ceramic honeycomb structural body, and method for preparing the same, which can satisfactorily support a catalyst and can demonstrate superior mechanical strength, even if far thinner walls are used. Said structural body comprises lattice walls formed by a large number of cells 10 which are channels for fluid and a peripheral wall 12 which covers at least the circumference of said lattice walls 11. The outer peripheral portion 112 of said lattice walls 11 located in the vicinity of said peripheral wall 12 (area B) contain a densified portion of smaller porosity than that of an inner peripheral portion 111, of said lattice walls 11, which is located inside said outer peripheral portion 112 (area A).