PROBLEM TO BE SOLVED: To provide an apparatus and a method for removing contaminants such as radioactive cesium.SOLUTION: A part of radioactive cesium included in water is removed by a first filtering part 41 having a silk filter attached to a paddy field inlet 111 for allowing water to flow into a paddy field (first filtering step). Then, water filtered by the first filtering part 41 is further filtered by a second filtering part 42 including a woven basket 31 having cocoons 11 in its inside (second filtering step). Where, each of the cocoons 11 includes zeolite in its inside.