The invention provides a plane mask ear band welding machine. The machine comprises an assembly plate, a conveying device, two ear band welding devices and two ultrasonic transducers; the conveying device comprises a driving mechanism, two conveying chains and jigs, wherein the two conveying chains are arranged in parallel with each other and side by side, the driving mechanism controls the two conveying chains to move, the jigs are separately positioned on the two conveying chains, and a plane mask is placed on the jigs; the assembly plate is positioned above the conveying chains in the vertical direction, the two ear band welding devices are arranged in a mirror image with respect to the jigs; the two ear band welding devices are arranged staggered in the moving direction of the conveying chains; and each ear band welding device comprises a fixing plate, a moving plate, a first cylinder, a linkage plate, two linkage rods, two pressure springs, two welding heads, a rotating disc, a driving motor, a second cylinder, a third cylinder, two abutting heads, two abutting plates and a yarn pressing plate. The plane mask ear band welding machine can produce inner ear masks and outer ear masks, and is convenient in operation, high in production efficiency and low in production cost.