We investigated cognitive processes of the information seeking on the WWW and the effects of subjects' knowledge and experience on their processes and performance through the protocol analysis. In our experiments, the subjects were assigned to an expert or a novice condition, and required to solve two search tasks. We analyzed the protocol data on the basis of the two space model of scientific discovery suggested by Simon & Lea (1981). We applied this model to the information seeking on the WWW. The information seeking processes on the WWW were considered as the processes of searching the Keyword space and the Web space . The experimental results showed that (1) due to the effects of knowledge and experience, the experts' performance of finding a target was higher than that of the novices, (2) when searching each space, the experts searched each space in detail but the novices did not, and (3) when shifting from one space to the other, the experts searched the two spaces alternately, but the novices tended to cling to a search of one of the two spaces.