Hexagonal faujasite (EMT) has two types of supercage whereas cubic faujasite (FAU) presents only one type of supercage. Using the same treatment than that for Pt clusters in a cubic faujasite, e.g. Y zeolite, a highly dispersed Pt cluster supported on EMT zeolite was prepared. The size, location and structure of Pt clusters entrapped in EMT was investigated using Xe-129 NMR spectroscopy, xenon adsorption, hydrogen chemisorption, high resolution electron microscopy (HREM) and extended X-ray absorption fine structure (EXAFS). The results suggest that a Pt cluster consisting of 20-30 Pt atoms is formed within the three-windows supercage of EMT. The size of Pt clusters does not depend on the Pt content in EMT, when the Pt/EMT obtained by the ion exchange of Pt(NH3)(4)(2+) is calcined in flowing O-2 at 573 K and subsequently reduced in flowing H-2 at 573 K.