This study investigates metacognition of digital library users who are engaged in information searching. Two research questions has set to examine 1) Do the digital library users self-monitor and self-assess their information searching process?; and 2) Can metacognitions that are employed for using a DL be characterized as that for general problem solving? If not, how they differ? Using Kim's reserch data on the information searching behaviors of a digital library, content analysis method was employed to find the evidences of metacognition of digital library users. The evidences were then matched against the twenty items of the "State Metacognitive Inventory" developed by the CRESST(NAtional Center for Research on Evaluation, Standards, and Student Testing). The results showed that infomation searching on digital libraries indeed involves metacognitive activities, and that metacognition that is being employed for searching digital library has extra dimensions of metacognition than that for general problem solving.