A metal side tube (2), a glass faceplate (3), and a stem plate ( ) constitute a hermetically sealed vessel (5) for a photomultiplier tube. An edge portion (20) is provided at on open end (A) of the side tube (2). The edge portion (2) is embedded in the faceplate (3) in such a manner as to strike on the faceplate (3). Accordingly, high hermeticity at a joint between the side tube (2) and the faceplate (3) is ensured. The edge portion (20) extends upright in an axial direction of the side tube (2), so that the edge portion (20) can be embedded as close to a side face (3c) of the faceplate (3) as possible. This structure increases an effective sensitive area of the faceplate (3) to nearly 100%, and decreases dead area as close to 0 as possible. As described above, the photomultiplier tube (1) according to the present invention has enlarged effective sensitive area of the side tube (3) and enhanced hermeticity of the joint between the faceplate (3) and the side tube (2).