To provide a ceramic substrate capable of preventing the occurrence of warp or waviness even when it is thin, and being manufactured at a low baking temperature, a piezo-electric actuator substrate and a piezo-electric actuator having stable piezo-electric characteristics, and manufacturing method for them.

The piezo-electric actuator substrate 17 is obtained by baking a laminated body 17 wherein a plurality of green sheets 12, 13, 14, with ceramic raw material powders as main components are laminated to a thickness of not more than 100 μm. In the laminated body 17, higher contraction layers 15, 16, with electrically conductive materials as main components having an average particle diameter of not more than 2 μm, have contraction factors larger than those of the green sheets 12, 13, 14 in the direction parallel to the surface upon baking. The higher contraction layers 15, 16 are laminated with the green sheets 12, 13, 14 so that, in the cross-section in the thickness direction of the laminated body 17, the layers 15, 16 are disposed to be symmetric about a line passing through a middle point of the thickness of the laminated body 17 and parallel to the surface of the laminated body 17. The piezo-electric actuator 11 is obtained by forming individual electrodes 18 on one surface of the piezo-electric actuator substrate 17.

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