In this study, we developed a hydrogen sensor based on a palladium microfiber network on a paper substrate. A 60-nm pure palladium film was deposited on photocopy paper using a vacuum evaporation technique. The photocopy paper was employed as the sensor substrate because of its low cost and the simple and rapid fabrication process. The texture of the microfiber network on the paper greatly increased the surface area to volume ratio for the palladium thin film, which is crucial for rapid response sensors. The experimental results showed that the hydrogen sensor exhibited a rapid response and linear gas response characteristics at room temperature and pressure. The gas response of the paper–substrate sensor was much higher compared with the glass substrate.