The objective of the present study is to exploit the feasibility of piezoelectric polymer film sensors to evaluate in-plane strain distributions of structural components. In contrast to ordinary use of piezoelectric films as strain and strain-rate sensors detecting electric charges and currents through electrodes, the proposed strategy consists of directly measuring the distribution of electric potentials induced in the piezoelectric film mounted on the surface of a structural component in loading. The stress and strain distributions are determined from the measured potentials taking into account the piezoelectric constitutive law of film materials. As an illustrative example, thin films of polarized polyvinylidene fluoride (PVDF) are mounted on a holed elastic plate subjected to in-plane loading, and the induced potential distributions are measured on the film surface by an electrostatic voltmeter of non-contact type. It is demonstrated that the determined strain distributions are in fair conformity with those analytically predicted.