Metal gutter expansion joint overflow leakproof connecting device

The invention discloses a metal gutter expansion joint overflow leakproof connecting device. The device comprises an upstream gutter and a downstream gutter and is characterized by further comprising a water collecting well, a rainwater hopper, an overflow ditch and a connecting part, wherein one end of the water collecting well is connected to the tail end of the upstream gutter, the interior of the water collecting well communicates with the rainwater hopper so that rainwater can be drained away, one end of the water collecting well is connected with the upstream gutter, the other end of the water collecting well is connected with the overflow gutter, the bottom face of the overflow gutter is higher than that of the upstream gutter, the portion, connected with the overflow gutter, of the downstream gutter is in a flaring mode, the tail end of the overflow gutter is arranged in the downstream gutter in a socket and spigot joint mode, and telescopic leakage-proof connection is formed through the connecting pa