A piezoelectric ceramic plate which is slightly deformed by firing, includes a plate-shaped substrate, and an electronic component. The piezoelectric ceramic plate has a pair of main surfaces, a pair of opposing first side surfaces, and a pair of opposing second side surfaces. The pair of first side surfaces are baked surfaces, and the distance between the pair of first side surfaces measured at the center in the longitudinal direction is denoted by Lc and the distance between the pair of first side surfaces measured at ends in the longitudinal direction is denoted by Le. The ratio of the difference ΔL between Le and Lc to Lc (ΔL/Lc) is 1.0% or less. The piezoelectric ceramic plate is suitably used as a piezoelectric ceramic plate having an area of each of the main surfaces of 360 mm2 or more and a thickness of 150 μm or less.