The present invention relates to a method of producing a cheese-like dairy product, characterized by adding at least 10 wt %, relative to the starting material milk, of water containing Paenibacillus sp. bacteria or water that has been treated with immobilized cells of Paenibacillus sp. Bacteria into starting material milk, followed by maintaining at a prescribed temperature, separating off the curd thus formed, and performing productization with or without further maturing; a cheese-like dairy product thus produced; and a water purifier packed with a support having Paenibacillus sp. bacteria immobilized thereon and a filter medium as a packing material.