The present invention provides a top-feeding double-swirl type gasifier: a feed line through which pulverized coal is supplied by nitrogen; a distributor for dividing the pulverized coal supplied; a plurality of burner nozzles for supplying the pulverized coal, divided in the distributor, and an oxidizer; a pressure reactor in which the pulverized coal and the oxidizer react with each other to produce a flow of synthesis gas; and a swirl generator for imparting a swirling force to the oxidizer which is fed into the pressure reactor, the gasifier further comprising a slag cooling and storing container placed beneath the pressure reactor. Each of the burner nozzles consists of a triple tube having a circular cross section. The pulverized coal and carrier gas are supplied to the most central region of the burner nozzle, and an oxidizer is supplied to an annular region 34 surrounding the central region.