A piezo-electric film forming method includes (1) a first moving step of moving a nozzle with respect to a substrate along a first direction to form a first piezo-electric band extending along the first direction, (2) a measuring step of measuring thickness distribution along the width of the first piezo-electric band, (3) a calculating step of calculating a shifting distance based on the thickness distribution, (4) a shifting step of moving the nozzle with respect to the substrate along a second direction by the calculated shifting distance, wherein the second direction intersects with the first direction, and (5) a second moving step of moving the nozzle with respect to the substrate along the first direction to form a second piezo-electric band extending along the first direction. The piezo-electric film is formed such that the first piezo-electric band and the second piezo-electric band are overlapped.