An electron multiplier includes an insulating substrate which includes an electrical wiring pattern and in which a through-hole is formed, an MCP arranged on one side of the through-hole of the insulating substrate and electrically connected to the electrical wiring pattern, a shield plate arranged in one side of the MCP and electrically connected to the MCP, an anode arranged on the other side of the through-hole and electrically connected to the electrical wiring pattern, and a signal readout terminal fixed to the insulating substrate for reading a signal from the anode. The shield plate is formed to include the MCP when viewed in a thickness direction. A through-hole exposing at least a portion of the MCP is formed in the shield plate. The insulating substrate, the MCP, the shield plate and the anode are fixed to each other to be integral.