An ignition safety device of a gas lighter. In an embodiment, the safety device comprises at least one protrusion provided on the ignition roller unit of the lighter. The protrusion may be formed on the knurled outer surface of the rolling shaft or on the rolling flanges of the roller unit. In another embodiment, the safety device comprises a transverse rod extending from one rolling flange toward the other rolling flange such that it crosses over the rolling shaft between the rolling flanges. One end of the transverse rod is connected to the inside surface of the one flange but the other end of the transverse rod is spaced apart from the inside surface of the other flange. The safety device provided on the ignition roller unit prevents more rotation of the rolling shaft when the rolling shaft has been rotated at a predetermined rotating angle and ignited the gas out of the nozzle. In order to return the ignition roller unit to a rotatable position, the roller unit is simply rotated in reverse direction such that the safety device is sufficiently spaced apart from the flint support column of the lighter body.