A control device is configured to control an air conditioner that includes an air conditioner outdoor unit and an air conditioner indoor unit. The control device includes a microcomputer and a storage element. The microcomputer causes a signal to be transmitted and received between an outdoor communication unit of the air conditioner outdoor unit and an indoor communication unit of the air conditioner indoor unit. The storage element stores specific information in response to command from the microcomputer. The microcomputer causes the storage element to store operation information including a state of transmission and reception of the signal of the air conditioner at a constant time interval.
