An ion detector includes a first dynode, a second dynode, a scintillator, a conductive layer, and a photomultiplier tube. The first dynode is configured to emit a charged particle in response to the incidence of the ion. The second dynode is configured to be given a negative potential and emit a secondary electron in response to incidence of the charged particle from the first dynode. The scintillator includes an electron incident surface arranged to receive the secondary electron from the second dynode, and is configured to convert the secondary electron into light. The conductive layer is disposed on the electron incident surface. The photomultiplier tube is configured to detect the light from the scintillator.