Pd-based membranes are one of the strong candidates for pure hydrogen production, because of their high hydrogen flux and almost complete hydrogen selectivity. Considerable efforts have been focused on preparation of Pd-based thin film on porous ceramic substrates to increase hydrogen flux and decrease membrane cost. However, the main drawbacks of the Pd-based supported film are relatively larger permeation resistance of the substrate itself and due to excess Pd penetration into the substrate pore, and long-term instability caused by a distorted force at membrane/substrate interface during heating/cooling cycles and/or repeated hydrogen adsorption/desorption. Moreover, the Pd-based supported films make construction, sealing, and handling of a metal-made membrane module difficult. To cope with these problems, a self-supported Pd-based thin film is more desirable. Preparation of self-supported Pd-based thin films by dry methods like sputtering and vapor deposition has already been reported. Those thin films were reported to have less than 10 μm in thickness and to exhibit some hydrogen separation performance. Here a simple and cost-effective wet preparation process was developed, where thin and defect-free self-supported Pd-based thin films were prepared. The self-supported Pd-based thin films built in a metal-made membrane module were shown to exhibit higher hydrogen flux, almost infinite selectivity and excellent membrane stability.