An apparatus for collecting a by-product, includes: a chamber provided with a gas inlet and a gas outlet and having an internal space; a heater disposed on the gas inlet side of the internal space within the chamber and varying a heating temperature in time series; a vortex forming member disposed around the heater; a plurality of first collecting members disposed below the heater; a second collecting member disposed below the first collecting member so that a plurality of second collecting members intersect each other; and a third collecting member disposed on the gas outlet side of the internal space within the chamber.