A cognitive radio (CR) system scans the wide spectrum to find available spectrum. One of key challenges in using these temporarily available spectrums is that the bandwidth of the available spectrum are not equally wide. The other challenge for spectrum decision scheme in CR systems is that many secondary users (SUs) may choose the same channel simultaneously, resulting in channel contention. In this paper, we develop a load balancing spectrum decision scheme for unequal-bandwidth CR networks. We apply the concept of the delay bandwidth (DB) product to select a suitable channel for each user among many unequal-width channels. Compared with other existing unequal bandwidth spectrum decision schemes, our simulation results show that the proposed DB-based spectrum decision can improve the overall system throughput up to 40\% in the considered case.