A plate-like polycrystalline particle is produced by forming inorganic particles into a freestanding shaped body, firing the shaped body, and crushing and classifying the fired shaped body. The inorganic particles contain as the main component an oxide that has a general formula of ABO3 and that satisfies a×Pb(M′1/3,Nb2/3)O3+b×PbTiO3+c×PbZrO3+z×M″O (wherein a+b+c=1, and M′ denotes at least one element selected from Mg, Ni and Zn, and M″ denotes at least one element selected from Mg, Ni and Zn), wherein z is in the range of 0.002≦z≦0.42. The oxide contains a predetermined excessive amount of M″O such that the plate-like polycrystalline particle contains an excessive amount of M″O. The plate-like polycrystalline particle contains a plurality of crystal grains that have a wavy structure composed of wavy grain boundaries. The plate-like polycrystalline particle is easily crushed at the grain boundaries and has a high degree of orientation.