The electrode mount includes a filament coil, paired lead wires supporting the filament coil therebetween in a manner that the filament coil hangs across the lead wires; and bead glass retaining the paired leadwires. The arc tube includes an arc tube main body formed by winding a glass tube, and an electrode fixed to the end portion of the arc tube main body. For this electrode, the electrode mount is used. The fixing of the electrode mount at the end portion of the arc tube main body is made at a region of the lead wires positioned between the filament coil and the bead glass, and the bead glass is disposed outside the arc tube main body.