To provide a siphon type rain gutter device capable of sucking out rainwater in an eaves gutter by a siphon effect even if an amount of rainfall is small.

An elbow 12 generating a siphon effect is connected to a bottom of an eaves gutter 7 provided at an edge of eaves, and a down-pipe 13 is connected to the elbow 12. A diameter of the down-pipe 13 is larger than the diameter of the elbow 12, so that an inside of the elbow 12 is easily filled with rainwater even if an amount of rainfall is small. As a result, the rainwater in the eaves gutter 7 can be forcefully sucked out by the siphon effect. The rainwater, which flows while the elbow 12 is fully filled with water by the siphon effect, falls in the down-pipe 13 by natural falling due to gravity. Since the diameter of the down-pipe 13 is larger than the diameter of the elbow 12, the rainwater flowing in the elbow 12 by the siphon effect can be smoothly drained.