In an apparatus for generating a test pattern for a sequential logic circuit including a plurality of storage elements each storage element storing a logical value of one bit wherein logical values of bits of the plurality of storage elements being represented by a state, first external input values are generated so that a transition process is performed from a second state of the plurality of storage elements to a first state thereof, and second external input values are generated so that a transition process is performed from a third state of the plurality of storage elements to the first state thereof. Thereafter, third external input values are generated so that a transition process is performed from a fourth state of the plurality of storage elements to the first state thereof. After setting the fourth state as the first state, name data of storage elements corresponding to bits of different states between the second and third states are stored in a storage unit. After setting the third state as the first state, there is increased a degree of requesting a scan operation for each of the storage elements, name data of which have been stored in the storage unit. Then, storage elements to be scanned are selected for generating an improved test pattern based on the degree of requesting the scan operation.
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