PURPOSE: To prevent freeze at a downward curve in a snow-carrying tubular conduit at the time of stopping of the forced feeding of snow by making a lid member open and close a drain hole.

CONSTITUTION: In a snow-carrying tubular conduit 12 provided along a laying line 7 corresponding to an undulating skiing slope a drain hole 12a is provided at a position corresponding to a pit 7b where the laying line 7 is bent downward. There is provided a draining mechanism 16 having a lid 19 which freely opens and closes and, when snow is carried, closed the drain hole 12a under the pressure of the forwarding air. When snow is carried, the lid 19 is made to close the drain hole 12 and snow is fed through a snow-carrying space 12s by a means for feeding snow under pressure; the snow is ejected from a discharge nozzle and spread on a slope. When this feeding of snow under pressure is stopped, the force of upheaval FU of a spring mechanism 20 acts and the lid 19 opens; with the snow-carrying space 12s opened to the outside, the snow remaining therein melts through rise of the air temperature and the water is discharged through a drain pipe 17.