A controller for an air conditioner, comprising: a communication device configured to communicate with the air conditioner; and an output device configured to display, on a management screen , information received from the air conditioner communicatively connected to the communication device , wherein, once the communication device is communicatively connected to the air conditioner, the output device receives product information of the air condition from the air conditioner and displays the management screen corresponding to the product information received, wherein, if the communication device is disconnected from the air conditioner and is connected to an another-type air conditioner, the communication device receives the product information from the another-type air conditioner, and the output device displays, on the management screen , the product information received from the another-type product information, wherein the output device displays, on the management screen , a product display region and a plurality of information display regions to display an operation state of the air conditioner, wherein a layout of the plurality of information display regions and a layout of the product display region on the management screen are constant regardless of a category or a type of the air conditioner communicatively connected to the communication device , wherein at least one of the plurality of information display regions displays, fixed information displayed being changed in terms of a display position on the at least one of the plurality of information display regions according to the category or type of the air conditioner, and variable information comprising common information displayed in common for air conditioners communicatively connected to the communication device , the air conditioners belonging to the same category; and individual information displayed individually for each of different types of air conditioners belonging to the same category. a communication device configured to communicate with the air conditioner; and an output device configured to display, on a management screen , information received from the air conditioner communicatively connected to the communication device , wherein, once the communication device is communicatively connected to the air conditioner, the output device receives product information of the air condition from the air conditioner and displays the management screen corresponding to the product information received, wherein, if the communication device is disconnected from the air conditioner and is connected to an another-type air conditioner, the communication device receives the product information from the another-type air conditioner, and the output device displays, on the management screen , the product information received from the another-type product information, wherein the output device displays, on the management screen , a product display region and a plurality of information display regions to display an operation state of the air conditioner, wherein a layout of the plurality of information display regions and a layout of the product display region on the management screen are constant regardless of a category or a type of the air conditioner communicatively connected to the communication device , wherein at least one of the plurality of information display regions displays, fixed information displayed being changed in terms of a display position on the at least one of the plurality of information display regions according to the category or type of the air conditioner, and variable information comprising common information displayed in common for air conditioners communicatively connected to the communication device , the air conditioners belonging to the same category; and individual information displayed individually for each of different types of air conditioners belonging to the same category. <EOS>