Based on a classic Galerkin scheme a piecewise-quadratic a posteriori error estimator (AEE) has been built for finite element method piecewise-linear approximation of a stationary piezoelectricity problem for elastic deformation and electric potential. In addition to energy error characteristics on a triangular element, the proposed AEE allows to calculate approximate point-values of errors in center of its sides. Using this AEE and Delaunay triangulation constructing algorithm an h-adaptive FEM schemehas been built, which convergence computing characteristics are illustrated by results of the solved model problem.