A fusion welding device including a first holder and a second holder where the respective holders are adapted to hold an end portion of a first work and a second work, respectively, such that the works are moveable in a longitudinal direction; a heater, operable to heat the first and second works; two movers adapted to move the first and second holders close to or apart from each other; and a third mover adapted to move the first and second holders in synchronization with each other in a direction along the first and second faces. The first and second holders are moved by the third mover where the first and second faces are in contact with each other, whereby end faces of the end portions of the first and second works are pressed to each other.