A monitoring system includes a first imaging device, a controller, storage, and a notifying section. The first imaging device captures an image of a first imaging area to generate first captured image data indicating a first captured image. The controller detects the events based on the first captured image data. The storage stores data indicating a first flag and a second flag. The events include a pre-event and a post-event detected after the pre-event has ended. The post-event indicates a detection target removal act for a detection target placed in the first imaging area. The controller changes the first flag from the off state to an on state upon detecting the pre-event, holds the first flag in the on state even after the pre-event has ended, changes the second flag from the off state to the on state upon detecting the post-event, and notifies of consecutive event occurrence information.