Abstract As reported previously, MgH 2 synthesized by hydriding chemical vapor deposition (HCVD) was made of single crystals with nano-fibrous figures. Therefore, the hydrogen storage property of the HCVDed MgH 2 is expected to reflect its structural character. In this study, we examined the hydrogen storage property of MgH 2 synthesized by HCVD. Results of pressure-composition-isotherm (PCT) measurement showed that the HCVDed MgH 2 reversibly absorbed and desorbed hydrogen as much as 7.6 mass% without any activation treatment retaining the fiber shape. Each hydrogenation/dehydrogenation rate was great because hydrogen diffused through a short pathway in a radial direction of the fiber.