PROBLEM TO BE SOLVED: To further improve sterilization efficiency of irradiation target bodies.SOLUTION: An ultraviolet irradiation module cell includes: a housing 4 having a hollow part a0 surrounded by a first end face 1, a second end face 2, and a cylindrical side face 3； a mounting part 5 for installing an ultraviolet irradiation device on the first end face 1 side of the housing 4； and a first partition 6 which is disposed in the hollow part a0 to section the hollow part a0 into two closed spaces and includes a first opening part 9 communicating the two spaces. From the second end 2 side, a second through-hole 8 is formed in the second end face 2 at a position facing a region on an inner side of the first partition 6. A first through-hole 7, which is provided in the second end face 2 at a position facing a region between the first partition 6 and the side face 3 or in the side face 3, and the first opening part 9 are disposed such that a distance between the first opening part 9 and the first through-hole 7 in a direction along an outer periphery of the first partition 6 becomes longer and also disposed on different sides along an extending direction with respect to the center of the extending direction of the first partition 6.SELECTED DRAWING: Figure 1
