The invention discloses a welding device. The welding device comprises a base, a cylinder, a push portion and a plug head portion, the cylinder is fixedly arranged above the base, the push portion is fixedly connected at the top of the cylinder and extends leftwards, a plugging groove is formed in the left end face of the cylinder, vertically symmetrical plugging springs are arranged on the inner right wall of the plugging groove, a sensor is arranged at the position, between the two plugging springs, of the inner right wall of the plugging groove, a mounting groove is formed in the top end face of the push portion, a sliding groove is formed in the left bottom end face of the push portion, a sliding cavity is formed in the push portion above the right side of the sliding groove, a force transfer cavity is formed in the position, on the right sides of the sliding cavity and the sliding groove, of the push portion, a first toothed wheel is arranged below the inner portion of the force transfer cavity, a second toothed wheel is connected to the top of the first toothed wheel in a mesh manner, a first rotating rod extending leftwards and rightwards is fixedly arranged on the first toothed wheel, and a second rotating rod extending leftwards and rightwards is fixedly arranged on the second toothed wheel. The welding device is simple in structure, convenient to operate, high in safety and capable of achieving plugging automatically and has a prompt function.