An automated valet parking system provides an automated valet parking service in a parking lot. Recognition result information is generated based on a result of recognition by a recognition sensor when a vehicle exists in the parking lot. The automated valet parking system identifies the vehicle position in the parking lot by using an infrastructure sensor installed in the parking lot. The automated valet parking system acquires expected recognition result information expected to be obtained at the vehicle position. Then, the automated valet parking system compares the recognition result information with the expected recognition result information to calculate reliability of the recognition result information based on a difference between them. When the reliability is lower than a threshold, the automated valet parking system transmits notification information for notifying an abnormality of the recognition sensor to a terminal device operated by a user of the vehicle.