It is to provide a mechanism where a sterilization process using a concentrated sterilizing agent and a sterilization process using a sterilizing agent that has not been concentrated can be switched without changing the sterilization process.In the case where the concentrated mode is received by receiving means the transfer of the sterilizing agent to the concentration chamber is controlled according to a first timing, and in the case where the non-concentrated mode is received by the receiving means, the transfer of the sterilizing agent to the concentration chamber is controlled according to a second timing, wherein the first timing is different from the second timing.
