Abstract: An optical-fiber fusion-splicing device includes: a first heating device in which a fusion-splicing operation of heating and fusing abutting parts of at least a pair of optical fibers with end faces brought into contact with each other is performed; a second heating device in which a reinforcing operation of heating and shrinking a heat-shrinkable resin which covers a site where the optical fibers are fusion-spliced to each other is performed; and a CPU which controls the first heating device and the second heating device, wherein the CPU preheats a heater of the second heating device so as to reach a predetermined first temperature, if the CPU receives a heating end signal from the first heating device, and thereafter, heats the heater of the second heating device so as to reach a second temperature higher than the first temperature, if the CPU receives a reinforcement start signal.