A fluid purification unit includes a case including a hollow and a plurality of openings communicating with the hollow to flow a fluid inside into the hollow and outside from the hollow, the case including combining protrusions formed on a first face and concave portions formed on a second face opposite to the first face, each of the combining protrusions having a first cross sectional area and being regularly arranged in a first direction and at a first interval and each of the concave portions having a second area corresponding to the first cross sectional area and being arranged at a second interval corresponding to the first interval.