A method of manufacturing a light emitting device having a plurality of nano-light emitting structures is provided. A geared motor includes a drive shaft, a reduction gear coupled to the drive shaft and having a transmission ratio less than 1, and a piezoelectric element selectively locking the drive shaft. The second metal film has been deposited on the first metal film and is made of a second metal having a work function located closer to the valence band of silicon with reference to the intermediate level of silicon bandgap. The auxiliary measured value is corrected using the calibration factor in order to form the structure size measured value.