To provide a vermin trap enabling easy assembling and monitoring works, taking consideration of the resource protection on the premise of the disposal of large quantities of the traps and useful for the investigation of the living state of vermin in a large-scale building such as a plant.

The vermin trap is composed of a sheet of an elastic plate to form a circular arch at the upper face by hooking the side edge of the upper face with a claw of the bottom side edge and is easily assemblable. Since at least a part of the upper face is transparent or semitransparent, the inside of the trap is easily viewable. The whole trap body may be transparent or semitransparent.