An isolator system including: a body case; a sterilizing unit; an air conditioning unit; a display unit; a control unit; and a storage unit, the control unit being configured to, after startup, confirm whether a concentration of a sterilizing substance in a work area is equal to or less than a predetermined concentration, or not, and when the concentration of the sterilizing substance exceeds the predetermined concentration, store a high concentration flag in the storage unit, and thereafter, check an operation of the air conditioning unit, if there is no problem with the operation of the air conditioning unit, confirm whether the flag is stored, and when the flag is stored, operate the air conditioning unit for a predetermined time period, to lower the concentration of the sterilizing substance, and when the flag is not stored, end check of the operation of the air conditioning unit.