A steak tube has a container with an entrance plate and an output plate, a photocathode disposed in the container and configured to emit electrons according to light to be measured, the light having been incident through the entrance plate, and a sweep electrode disposed in the container, having a pair of deflection plates for generating an electric field and a connection lead connected to each deflection plate, and configured to sweep the electrons in a sweep direction along the output plate. An opposing of edges of the deflection plate in a direction of the output plate are formed so as to extend in a direction from the entrance plate to the output plate, the connection lead has a first connection portion electrically connected to the deflection plate, and the first connection portion is connected to the opposing of edges.