The present invention provides an arc-preventing apparatus for separate cord-type hair dryer to prevent from being damaged by an arc which is occurred when a male connector formed at one end of a separate-type power source cord is disconnected to a female connector installed in a main body of the hair dryer under a load condition. The arc-preventing apparatus is installed in a power contact unit of the hair dryer, and the male and the female connector are fixed or released by an on/off switch of the hair dryer. The arc-preventing apparatus comprises a stopper formed in one side of the female connector which is installed in the power contact unit of the main body, and protruded or retracted by a first elastic body; a rod inserted into a rotation shaft formed in the side opposite to the stopper, and rotates by a predetermined angles along a second elastic body and a guide groove, as the on/off switch is moved down; and a male connector having a first and a second stopping groove which are coupled to a stopping protrusion formed in one end of the rod and the stopper, respectively.