The invention is a discharge system (1) including: a head unit (10) comprising a discharge head (11) for discharging a liquid (25) to a target (51) from a nozzle opening (14) communicating with a cavity (13), the internal pressure of the cavity (13) being altered by a piezoelectric element (12); a viscosity estimation unit (81) for estimating the viscosity of the liquid (25) by suctioning the liquid (25) into the cavity (13) from a first vessel (21) which holds the liquid (25); and a waveform control unit (82) for controlling the voltage applied to the piezoelectric element (12), depending on the estimated viscosity of the liquid (25).