A retrieval unit retrieves examination information: that includes the identification information on an endoscope corresponding to the identification information on an endoscope included in cleaning information； and in which an examination end time included in the examination information is prior to a cleaning start time included in the cleaning information. An association candidate determination unit determines, of examination information that satisfy a retrieval condition, examination information including an examination end time closest to the cleaning start time as a candidate for the examination information that should be associated with the cleaning information. A time conversion unit converts a cleaning start time of standard time included in the cleaning information into a cleaning start time of summer time. A retrieval unit re-retrieves examination information by using the converted cleaning start time of summer time.
