A photomultiplier eliminates the reflection of light off of focusing pieces in a focusing electrode and prevents the photocathode from emitting useless electrons in response to such reflected light by including an oxide film formed over the surface of each focusing piece. The oxide film is also formed on the surface of secondary electron emission pieces in the first and second stage dynodes to eliminate the reflection of light off of the secondary electron emission pieces and to prevent the photocathode from emitting useless electrons in response to such reflected light. Further, a light-absorbing glass partitioning part is provided in a light-receiving faceplate to suppress crosstalk between channels.