A verification test is performed on a device containing master and slave units connected via a bus. In the verification test, a first signal is transferred between a first master unit and a first slave unit during a first transfer period while a second signal is transferred between a second master unit and a second slave unit during a second transfer period. The second transfer period overlaps at least a part of the first transfer period. When the first transfer period is longer than a third transfer period, first combination information indicating the combination of the first master unit and first slave unit is stored in a storage unit, in conjunction with second combination information indicating the combination of the second master unit and second slave unit.