PURPOSE: A polymeric material for a pyroelectric engine, which has an extremely high efficiency of energy conversion and practicality, comprising a polymeric material showing a dielectric phenomenon of undergoing phase transfer from ferroelectric to paraelectric one with a changes in temperature.

CONSTITUTION: A polymeric material for a pyroelectric engine, comprising polymeric material showing a dielectric phenomenon of undergoing phase transfer from ferroelectric to paraelectric one with changes in temperature (e.g., vinylidene fluoride/trifluoroethylene copolymer of a vinylidene fluoride content of 30W90mol%). Heretofore, there has been an idea of a pyroelectric engine in which heat is recovered as an electric energy by using a ferroelectric ceramic such as PZT, but it could not be realized because of an extremely low efficiency of thermoelectric energy conversion. The use of the polymeric material of this invention can realize the practical use of a pyroelectric engine because of its extremely high efficiency of energy conversion.