In an evaporation source, a separable heater is used when an organic thin film is formed on a substrate in order to realize full-colors so that it is possible to correspond to crucibles of various capacities. The evaporation source comprises a crucible in which an organic material which is an organic thin film material is accommodated, and the crucible includes a heating unit and at least one spray nozzle for spraying the organic material onto a substrate. In the heating unit, a heater divided into at least two parts is provided on the external surface of the crucible at uniform intervals, and the heaters are separately disposed with respect to each other, but are connected to each other by connecting members. Therefore, it is not necessary to perform an additional design whenever the capacity of the crucible is changed, it is not necessary to exchange the evaporation source, and it is possible to reduce cost and to improve repairing ability.