PROBLEM TO BE SOLVED: To provide a fishing bank/seaweed bank block capable of providing an environment similar to the natural environment in which fishes and small animals live, and a method of forming a fishing bank/seaweed bank.SOLUTION: The block 1 is formed with a coal-ash particulate material 2 made of granulated coal ash as an aggregate. The coal-ash particulate material 2 is formed from raw materials containing coal ash and slag cement generated in a coal thermal power plant. The block 1 is subjected to a neutralization process with carbon dioxide. Since the block 1 is formed with the carbon-ash particulate material 2, whose raw materials are coal ash and slag cement generated in the coal thermal power plant, as the aggregate, seaweeds or the like can be implanted in the block in a state similar to the natural environment. Since the block 1 is porous and projections and recesses are formed on the surface, seaweeds or the like can be easily implanted on the surface of the block 1. Further, since the block 1 is subjected to the neutralization process with carbon dioxide, high alkalization of water in the periphery caused by elution of alkali components can be prevented even if the block is set under water.
