A bus control circuit configured to transfer access commands for performing exclusive access between a first bus specification and a second bus specification, the bus control circuit configured to convert a first exclusive access command into a second exclusive access command, the first exclusive access command including a first format applying to the first bus specification which provides exclusive access and being an access command previously prepared based on the first bus specification, the second exclusive access command including a second format applying to the second bus specification which does not provide exclusive access, and using a certain bit field in the second bus specification indicating an exclusive access, the bus control circuit comprising: an exclusive access command conversion circuit (A-1) configured to receive a first outgoing exclusive access command, convert the first outgoing exclusive access command into a second outgoing exclusive access command, and output the second outgoing exclusive access command, when the bus control circuit is configured to convert the first outgoing exclusive access command into the second outgoing exclusive access command; an exclusive access response receiving circuit (B-2) configured to receive exclusive access command response information in response to the second outgoing exclusive access command and configured to issue exclusive access command response information for the second outgoing exclusive access command to the exclusive access command conversion circuit (A-1), when the bus control circuit is configured to convert the first outgoing exclusive access command into the second outgoing exclusive access command; an exclusive access command generation circuit (B-1) configured to receive a second incoming exclusive access command, generate a first incoming exclusive access command, and receive an exclusive access command response for the first incoming exclusive access command, and issue an exclusive access command response information for the first incoming exclusive access command to an exclusive access response issuing circuit (A-2), based on the exclusive access command response for the first incoming exclusive access command, when the bus control circuit is configured to generate the first incoming exclusive access command from the second incoming exclusive access command; and the exclusive access response issuing circuit (A-2) configured to issue exclusive access command response information received from the exclusive access command generation circuit (B-1) in response to the second incoming exclusive access command, when the bus control circuit is configured to generate the first incoming exclusive access command from the second incoming exclusive access command. an exclusive access command conversion circuit (A-1) configured to receive a first outgoing exclusive access command, convert the first outgoing exclusive access command into a second outgoing exclusive access command, and output the second outgoing exclusive access command, when the bus control circuit is configured to convert the first outgoing exclusive access command into the second outgoing exclusive access command; an exclusive access response receiving circuit (B-2) configured to receive exclusive access command response information in response to the second outgoing exclusive access command and configured to issue exclusive access command response information for the second outgoing exclusive access command to the exclusive access command conversion circuit (A-1), when the bus control circuit is configured to convert the first outgoing exclusive access command into the second outgoing exclusive access command; an exclusive access command generation circuit (B-1) configured to receive a second incoming exclusive access command, generate a first incoming exclusive access command, and receive an exclusive access command response for the first incoming exclusive access command, and issue an exclusive access command response information for the first incoming exclusive access command to an exclusive access response issuing circuit (A-2), based on the exclusive access command response for the first incoming exclusive access command, when the bus control circuit is configured to generate the first incoming exclusive access command from the second incoming exclusive access command; and the exclusive access response issuing circuit (A-2) configured to issue exclusive access command response information received from the exclusive access command generation circuit (B-1) in response to the second incoming exclusive access command, when the bus control circuit is configured to generate the first incoming exclusive access command from the second incoming exclusive access command.