An apparatus for preventing backflow of a gas of a scroll compressor includes: a hermetic container provided with a discharge pipe through which a gas is discharged; a fixed scroll fixedly coupled in the hermetic container; an orbiting scroll orbiting in meshing engagement with the fixed scroll to compress gas together with the fixed scroll; and a backflow preventing means for preventing backflow of a gas discharged through the discharge pipe. Therefore, a gas compressed by an orbiting movement of the fixed scroll and the orbiting scroll is smoothly discharged to the discharge pipe through the hermetic container during operation of the compressor, and the gas discharged to the discharge pipe is prevented from backflowing into the hermetic container when the operation is stopped.