PURPOSE: To provide both functions of a cold trap and a Cs trap by incorporating the Cs trap inside the cold trap, moving the Cs trap up and down and controlling the flow of a cooling material.

CONSTITUTION: An internal container 11 with a built-in removing material 10 for removing radiation substances like Cs and the like existing in the cooling material is disposed in a container 2 with a built-in removing material 5 for removing impurities such as oxygen existing in the cooling material. That is, a Cs trap is incorporated inside a cold trap, and the flow of the cooling material can be controlled by moving the Cs trap up and down, by which the flow can be changed over and the cold trap can be used as the Cs trap, and the necessity of disposing both traps in parallel or in series as is in the systems heretofore available is eliminated to make a plant equipment light in weight and compact to a large extent and reduce the cost to a substantial extent.