A control terminal device comprising: a display unit ; and a control unit (1; 20) configured to display a list screen of a plurality of reproduction devices on the display unit based on relationship information between the plurality of reproduction devices which is connected via network , receive selection of a reproduction device as a target which is made to perform a content reproduction operation among the plurality of reproduction devices , and transmit a command to the reproduction device selected as the target; wherein the relationship information includes pair setting information on setting a pair of reproduction devices ; and wherein the control unit (1; 20) is configured to display the list screen where the plurality of reproduction devices which are set as the pair are integrated into one based on the pair setting information; wherein one reproduction device among the plurality of reproduction devices which are set as the pair is set as a parent device, and the other reproduction device is set as a child device, the parent device being in charge of communication with other devices, wherein the control unit (1; 20) is configured to transmit an updated reproduction parameter and an update command only to the parent device and the parent device transmits the updated reproduction parameter and the update command to the child device, the update command being a command to instruct update of a reproduction parameter, the reproduction parameter being setting information of an equalizer, and the control unit (1; 20) displays the reproduction device that is the parent device and does not display the reproduction device that is the child device on the list screen based on the pair setting information. a display unit ; and a control unit (1; 20) configured to display a list screen of a plurality of reproduction devices on the display unit based on relationship information between the plurality of reproduction devices which is connected via network , receive selection of a reproduction device as a target which is made to perform a content reproduction operation among the plurality of reproduction devices , and transmit a command to the reproduction device selected as the target; wherein the relationship information includes pair setting information on setting a pair of reproduction devices ; and wherein the control unit (1; 20) is configured to display the list screen where the plurality of reproduction devices which are set as the pair are integrated into one based on the pair setting information; wherein one reproduction device among the plurality of reproduction devices which are set as the pair is set as a parent device, and the other reproduction device is set as a child device, the parent device being in charge of communication with other devices, wherein the control unit (1; 20) is configured to transmit an updated reproduction parameter and an update command only to the parent device and the parent device transmits the updated reproduction parameter and the update command to the child device, the update command being a command to instruct update of a reproduction parameter, the reproduction parameter being setting information of an equalizer, and the control unit (1; 20) displays the reproduction device that is the parent device and does not display the reproduction device that is the child device on the list screen based on the pair setting information. <EOS>