In this paper, a new principle for measuring sea waves is suggested, and a wave recorder of equal-resistance contact type has been designed and constructed. Results of laboratory experiments and field works prove that the linearity of this method is satisfactory, and meanwhile the zero-line can be recorded. It is suitable for measuring waves in different regions of the sea, and can be operated with synchronous measurement of other oceanic dynamic elements and without interference. Furthermore, in the electrical circuit, the connetive usage with recording system is considered. It provides, for the self-observation of sea waves, a simple and light instrument which is appropriate to manufacture by sets.