A developing device and an image forming apparatus having the same are provided. The developing device includes: a housing, which is formed by coupling an upper case and a lower case and in which a developing roller and a regulating blade are installed; sealing elements, which are respectively formed at both sides of the developing roller or the regulating blade and prevent toner from leaking out of the housing; and fixing elements, which fix the sealing elements in the housing so that the sealing elements cannot move. Each of the fixing elements includes a supporting element, which expands the area of a corresponding fixing element and supports the corresponding sealing element by pushing the corresponding sealing element toward the regulating blade and the developing roller so that the corresponding sealing element comes into contact with the regulating blade and the developing roller.