An image forming apparatus includes a substrate, an electron-emitting device, a wiring electrode for applying an input signal to the electron-emitting device, and an image forming member to which an electron emitted from the electron-emitting device is irradiated. An acceleration electrode is provided opposite to the substrate, and a potential defining electrode is provided between the acceleration electrode and the substrate. A second support member connects the potential defining electrode and the acceleration electrode, and a first support member connects the wiring electrode and the potential defining electrode. The second support member has a semiconductive material surface, and the first support member has a resistance greater than that of the second support member by ten times or more.