To provide a snow melting device for a rain gutter capable of efficiently melting snow deposited in the gutter by skillfully utilizing air warmed up by geothermal energy and in rooms, smoothly draining snowmelt water from a roof, and preventing rotting of the roof and rain water leakage.

A cover board 2 covering and concealing the side portion to bottom portion at the eaves side of a rain gutter main body 1 is continuously formed along the longitudinal direction of the upper end edge at the eaves side in the rain gutter main body 1 by maintaining a space to the rain gutter main body 1, the roof side of the rain gutter main body 1 where the space is opened is fixed to a fascia board surface 10 with fixing means 19, and a space separated by the rain gutter main body 1, cover board 2 and the fascia board surface 10 is formed. A warm air supply hole 11 opened to the space 7 is provided along the longitudinal direction of the fascia board surface, and a jet hole 6 for sending warm air to a rain waterway 5 of the rain water gutter main body 1 and communicating with the space 7 is provided near the upper end edge along the longitudinal direction of the rain gutter main body 1.