A potassium niobate deposited body in accordance with an embodiment of the invention includes an R-plane sapphire substrate, and a potassium niobate layer or a potassium niobate solid solution layer formed above the R-plane sapphire substrate, wherein the potassium niobate layer or the potassium niobate solid solution layer epitaxially grows in a (100) orientation in a pseudo cubic system expression, and the potassium niobate layer or the potassium niobate solid solution layer has a (100) plane that tilts with a [11-20] direction vector as a rotation axis with respect to an R-plane (1-102) of the R-plane sapphire substrate.