Roof tile with prevention of adverse water

The present invention relates to a roof tile capable of preventing a backflow and, more particularly, to a roof tile capable of preventing a backflow characterized in that an upper flange, which has a drain groove, and a drain channel, along which rainwater is drained, are formed on the outer surface of the body of the tile; a lower flange is formed on the inner surface of the body, the lower flange having guide protrusions for discharging frost, an inner surface for preventing a backflow of rain drops (S), and an auxiliary protrusion portion; a drain groove and a drain channel are formed on the upper flange on the outer surface of the body, the drain groove penetrating the upper flange in the up/down direction, and the drain channel being arranged on the lower portion of the upper flange and being shaped to be open downwards such that rainwater is drained; guide protrusions and an auxiliary protrusion are formed on the inner surface of the body, the guide protrusions being arranged on the lower portion of an