A droplet forming method, for forming a droplet 27, constituted of a sample liquid 21, on a substrate 5 by applying a pulse voltage P between the sample liquid 21, retained in a nozzle 3, and the substrate 5, disposed opposite a tip of the nozzle 3, to discharge the sample liquid 21 from the tip of the nozzle 3, includes: a waveform measuring step S1 of measuring a temporal waveform of a current I that flows between the sample liquid 21 in the nozzle 3 and the substrate 5; and an application condition determining step S2 of determining, based on the temporal waveform of the current I, an application condition of the pulse voltage P during the forming of the droplet 27 on the substrate 5.