The present invention relates to the field of electric appliance such as AC/DC relay, AC/DC contactor and AC/DC low-voltage apparatus, and in particular, to a vent structure formed on the housing of an electric appliance. In one preferred embodiment, the present invention provides a vent structure for the housing of an electric appliance, the vent structure is defined by a clearance between a first wall and a second wall formed on the housing, the clearance is located between a first surface of the first wall and a second surface of the second wall, wherein the first wall and the second wall are not in the same plane. According to the present invention, a specific die is adopted in molding such housing. By the engagement between the male and female die inserts in the die, the vent structure in the housing of an electric appliance has a staggered and drop structure.