In this paper, we propose a test generation method for large scale sequential circuits based on circuit partitioning to increase the size of circuits that the implicit product machine traversal (IPMT) method can handle. Our method paratitions a circuit under test into subset circuits with only single output, and performs a partial scan design using the state transtition cost that represents a degree of the connectivity of the subset circuit. The IPMT method is applied to the partitioned partial scan circuits in test generation. Experimental results for ISCAS89 benchmark circuits with more thatn 50 flip-flops show that our method has generated test patterns with almost 100% fault coverage at high speed by use of 34%-73% scanned flip-flops.