An apparatus for manufacturing fine particles includes a reactor; a first inlet part including at least one port introducing a reactive gas flow containing a fine particle source material; a second inlet part including at least one port introducing a diluting gas flow; a heater exciting the fine particle source material in the reactive gas flow; a first plate including through-holes which substantially equalize a flow rate of the reactive gas flow with respect to a cross section of a flow channel; a second plate including through-holes which substantially equalize a flow rate of the diluting gas flow with respect to a cross section of a flow channel; a gas exhaust port provided in a merging region where the reactive gas flow passed through the first plate and the diluting gas flow passed through the second plate are merged; and a collector which collects fine particles.