Recently environmental pollution at sea becomes serious, so every governmental organization makes its effort to solve this problem. Combustible ocean wastes as of ropes, fishing nets, and tires are usually highly polymerized compound materials. The problem of ocean waste treatment can be solved by using the pyrolysis method. Pyrolysis characteristics of ocean waste was examined to get the basic data for the production system of fuel from the ocean waste. Thermogravimetric experiment showed that residual mass rate decreases as the velocity of temperature-rising becomes lower. The pyrolysis of waste rope and fishing net occurs at 300~450$^{circ}C $ and the waste tire does at 350~450$^{circ}C $. Pyrolysis time is estimated about 15 to 20 minutes in the temperature range when lively act of pyrolysis temperature reached.