Provided is a grain puffing apparatus which includes: a motor； a screw； a first screw spiral； a second screw spiral； a thread hitch； a screw groove； a cylinder； first and second cylinder spirals； a grain inlet unit； and a puffing unit which rapidly gushes grains that are changed into the gel state by the screw and the cylinder so as to be puffed. Here, the grain puffing apparatus puffs grains without a special heating apparatus, and efficiently discharges heat generated in the inside of the grain puffing apparatus and enables puffing of grains without stopping of operation.
