To make the display of history information of events easy to see.

An air conditioning monitoring system comprises a plurality of air conditioners, a central air conditioning monitoring unit for monitoring and controlling the air conditioners, and a communication circuit for transmitting signals between the central air conditioning monitoring unit and the air conditioners. The central air conditioning monitoring unit has a display unit and a memory for storing events of the air conditioners and the date and time of occurrence of the events. The monitoring system displays on the display unit the events and the date and time of the occurrence of the events. When the time interval between the date and time of the event to be displayed and the date and time of the event displayed last is within a specified range, a predetermined symbol (↓) is displayed instead of the date and time of the event to be displayed.