Provided is a substance mixing apparatus including two or more flow paths in which orifices, from which a fluid that flows therethrough is externally discharged, are formed, oscillation devices that form droplets of the fluid discharged from each of the orifices by oscillating at least the orifice part of the flow paths at a predetermined oscillation frequency and discharge the droplets, and means for causing the droplets discharged from the orifices of the flow paths to collide with one another.