Blowing device and welding device

The utility model relates to the technical field of welding, and provides an air blowing device and a welding device.According to the air blowing device, a first cylindrical wall arranged on the outer side and a second cylindrical wall arranged on the inner side are used for forming an overflowing gap, and then air can flow in from the air inlet side of the overflowing gap and flow out from the air outlet side of the overflowing gap; the thickness value of the overflowing gap meets the condition that Y is larger than or equal to Q/15, so that gas can evenly enter the overflowing gap and flow in the overflowing gap at the relatively smooth speed, the time for the gas to fully flow in the overflowing gap is given, and therefore when the gas flows out of the gas outlet side of the overflowing gap, the flowing speed of the gas is increased. According to the gas blowing device, the gas environment with the good consistency can be provided on the gas outlet side of the overflowing gap, when the gas blowing device i