An analysis device includes an electron emission element, a collector, an electric field former, a power source, and a controller. The electron emission element includes a bottom electrode, a surface electrode, and an intermediate layer arranged between the bottom electrode and the surface electrode. The power source and the controller allow application of a voltage between the bottom electrode and the surface electrode. The electric field former forms an electric field in an ion movement region where anions directly or indirectly generated by electrons emitted from the electron emission element move toward the collector. The collector and the controller allow measurement of a current waveform of an electric current made to flow by arrival of anions at the collector. The controller regulates, based on the current waveform, a voltage applied between the bottom electrode and the surface electrode.