A portable electronic apparatus, comprising: a communication unit for performing data communication with an external device; a controller for performing the data communication of the communication unit by using a logical channel selected from a plurality of logical channels; and a data storage unit for storing data in units of data as a target to access, according to a command from the external device, at least some of the units of data being un-shareable; and a command processor for performing access to a unit of data specified by the command received by the communication unit, on a logical channel specified by the command, characterized by further being configured to output to the external device in response to the command, a response message comprising: (i) a data part including first information (DATA1) storing data read as a result of successfully executing the command, second information (DATA2) indicating an identifier of an un-shareable unit of data and third information (DATA3) indicating an identifier of a logical channel used for accessing the un-shareable unit of data indicated by the second information or indicating an unused state of the un-shareable unit of data indicated by the second information; and (ii) a status part including information representing an execution result of the command, wherein, in a case where the unit of data specified by the command is an un-shareable unit of data to which access on the logical channel specified by the command cannot be successfully performed because the unit of data specified by the command is being accessed using a logical channel other than the logical channel specified by the command, the second information indicates an identifier of the unit of data specified by the command, the third information indicates an identifier of the logical channel other than the logical channel specified by the command, and the execution result of the command indicates that the command is abnormally terminated because the unit of data specified by the command is being accessed using a logical channel other than the logical channel specified by the command. a communication unit for performing data communication with an external device; a controller for performing the data communication of the communication unit by using a logical channel selected from a plurality of logical channels; and a data storage unit for storing data in units of data as a target to access, according to a command from the external device, at least some of the units of data being un-shareable; and a command processor for performing access to a unit of data specified by the command received by the communication unit, on a logical channel specified by the command, characterized by further being configured to output to the external device in response to the command, a response message comprising: (i) a data part including first information (DATA1) storing data read as a result of successfully executing the command, second information (DATA2) indicating an identifier of an un-shareable unit of data and third information (DATA3) indicating an identifier of a logical channel used for accessing the un-shareable unit of data indicated by the second information or indicating an unused state of the un-shareable unit of data indicated by the second information; and (ii) a status part including information representing an execution result of the command, wherein, in a case where the unit of data specified by the command is an un-shareable unit of data to which access on the logical channel specified by the command cannot be successfully performed because the unit of data specified by the command is being accessed using a logical channel other than the logical channel specified by the command, the second information indicates an identifier of the unit of data specified by the command, the third information indicates an identifier of the logical channel other than the logical channel specified by the command, and the execution result of the command indicates that the command is abnormally terminated because the unit of data specified by the command is being accessed using a logical channel other than the logical channel specified by the command.