Provided is an autonomous operation system, comprising an autonomous operation device (6100) and a second device independent of the autonomous operation device (6100). The autonomous operation system comprises a control circuit (200, 500, 600). The control circuit (200, 500, 600) comprises: a rainfall sensor (50, 640) comprising a first electrode (51) and a second electrode (52); a switching circuit (10) connected to the first electrode (51) and the second electrode (52), and configured to operatively switch polarities of the two electrodes; a detection module (22) configured to acquire an electrical signal of the rainfall sensor (50, 640); a determination module (23) configured to determine whether or not the electrical signal and a first threshold satisfy a first relationship; and a behavior control module (24) configured to control the autonomous operation device (6100) to change an operating state when it is determined that the electrical signal and the first threshold satisfy the first relationship.