A UV sensor (1) includes a container (5) in which the upper end opening of a metal side tube (2) is sealed with a front plate (3) composed of borosilicate glass as an incident light window and the lower end opening is sealed with a base plate (4). The front plate (3) serving as an incident light window constitutes part of the wall of container (5) by sealing the upper end opening of the metal side tube (2). A pin-type photodiode (6) is disposed inside the container (5). The pin-type photodiode (6) comprises a photoabsorption layer (9) formed from InxGa(1−x)N (0