The diffraction of a plane electroelastic shear wave on semi-infinite parallel racks in a piezoelectric space is considered. The presence of semi-infinite cracks leads to the propagation of diffracted shear waves in the piezoelectric medium–volume waves and surface waves localized at the free surfaces of cracks. The problem of diffraction of a shear plane wave by a semi-infinite crack is also studied in the case where there is a plane without acoustic contact (an infinite crack) in the piezoelectric space. The problems are reduced to solving Riemann-type problems on the real axis in the theory of analytic functions. Some features of the wave field have been revealed, which appear as a result of the diffraction of a plane shear wave on semi-infinite cracks and the interaction of physical fields—the piezoelectric effect.