A welding device, comprising: a drive unit, a first connecting rod, a second connecting rod, a welding head and a welding base; wherein the drive unit is in driving connection with one end of the first connecting rod and one end of the second connecting rod; another end of the first connecting rod is in driving connection with the welding head, and is configured for causing, being driven by the drive unit, the welding head to move in a direction close to or away from the welding base; and another end of the second connecting rod is in driving connection with the welding base, and is configured for causing, being driven by the drive unit, the welding base to move in a direction close to or away from the welding head, characterized in that the welding device further comprises two cams and at least one output shaft being in driving connection with the drive unit and mated with the two cams; wherein the one end of the first connecting rod and the one end of the second connecting rod are connected with one of the two cams; one output shaft is provided, and the output shaft penetrates through and is fixed to the two cams; the welding device further comprising a first stationary shaft and two drive rods; wherein the first stationary shaft is axially parallel to the output shaft; the two drive rods are rotatably disposed on the first stationary shaft in a circumferential direction of the first stationary shaft; the two drive rods each comprise a connecting part and a drive part, and two drive parts are respectively in driving connection with one of the two cams; and one end of the first connecting rod and one end of the second connecting rod are in driving connection with one connecting part. wherein the drive unit is in driving connection with one end of the first connecting rod and one end of the second connecting rod; another end of the first connecting rod is in driving connection with the welding head, and is configured for causing, being driven by the drive unit, the welding head to move in a direction close to or away from the welding base; and another end of the second connecting rod is in driving connection with the welding base, and is configured for causing, being driven by the drive unit, the welding base to move in a direction close to or away from the welding head, characterized in that the welding device further comprises two cams and at least one output shaft being in driving connection with the drive unit and mated with the two cams; wherein the one end of the first connecting rod and the one end of the second connecting rod are connected with one of the two cams; one output shaft is provided, and the output shaft penetrates through and is fixed to the two cams; the welding device further comprising a first stationary shaft and two drive rods; wherein the first stationary shaft is axially parallel to the output shaft; the two drive rods are rotatably disposed on the first stationary shaft in a circumferential direction of the first stationary shaft; the two drive rods each comprise a connecting part and a drive part, and two drive parts are respectively in driving connection with one of the two cams; and one end of the first connecting rod and one end of the second connecting rod are in driving connection with one connecting part.