A system debugging device in which, even if bus ownership is transferred to other bus masters, the operations of the other bus masters can be monitored such that efficient debugging of a system can be achieved is provided. In a system where a plurality of bus masters mounted on an LSI share a bus, the system debugging device includes a recorder for recording a variety of information including master selection information for specifying a bus master to which a right to use the bus is granted and slave selection information for selecting a bus slave specified according to address signals outputted from the bus master; and a reader for reading, via the bus, the variety of information recorded in the recorder.