The present invention provides: a biological electrode composition formable a living body contact layer for a biological electrode which is excellent in conductivity and biocompatibility, as well as light in the weight thereof and producible at a low cost, and in addition, which does not cause a significant decrease in the conductivity thereof regardless of under a water-wet condition and a dry condition; a polymer compound which can be suitably used for the biological electrode composition; a polymerizable monomer suitable as a raw material of the polymer compound; a biological electrode having a living body contact layer formed of the biological electrode composition; and a method for producing the same; and wherein, the polymerizable monomer is represented by the following general formula (1).