A dishwasher comprising: a cabinet; a washtub provided within the cabinet to wash tableware therein; a steam supplier that selectively supplies either steam or superheated steam to the washtub; and wherein the steam supplier comprises: a steam generator generating the steam by heating water; and a superheater (100, 200, 300) generating the superheated steam by heating the steam generated by the steam generator, characterized in that the dishwasher comprises a control panel having an input unit to select one of a steam-using operation course and a superheated-steam-using operation course, wherein the input unit includes a course selecting unit for selecting a sanitary course enabling the steam generator to be activated only or a powerful sterilization course enabling both of the steam generator and the superheater (100, 200, 300) to be simultaneously activated, wherein the dishwasher is configured such that if a user selects the sanitary course, the steam is supplied at the defaulted steam time and for the defaulted steam period and if the user selects the powerful sterilization course, the superheated steam is supplied at the defaulted steam time and for the defaulted period, wherein the control panel further having an option selecting unit having a plurality of course selecting parts, the option selecting unit enabling the superheated steam to be additionally used for the course, wherein the user is able to select a different value to steam time and a different value for steam period, other than those stored as the default values of the steam time and steam period, by using the option selecting unit. a cabinet; a washtub provided within the cabinet to wash tableware therein; a steam supplier that selectively supplies either steam or superheated steam to the washtub; and wherein the steam supplier comprises: a steam generator generating the steam by heating water; and a superheater (100, 200, 300) generating the superheated steam by heating the steam generated by the steam generator, characterized in that the dishwasher comprises a control panel having an input unit to select one of a steam-using operation course and a superheated-steam-using operation course, wherein the input unit includes a course selecting unit for selecting a sanitary course enabling the steam generator to be activated only or a powerful sterilization course enabling both of the steam generator and the superheater (100, 200, 300) to be simultaneously activated, wherein the dishwasher is configured such that if a user selects the sanitary course, the steam is supplied at the defaulted steam time and for the defaulted steam period and if the user selects the powerful sterilization course, the superheated steam is supplied at the defaulted steam time and for the defaulted period, wherein the control panel further having an option selecting unit having a plurality of course selecting parts, the option selecting unit enabling the superheated steam to be additionally used for the course, wherein the user is able to select a different value to steam time and a different value for steam period, other than those stored as the default values of the steam time and steam period, by using the option selecting unit. a steam generator generating the steam by heating water; and a superheater (100, 200, 300) generating the superheated steam by heating the steam generated by the steam generator, characterized in that the dishwasher comprises a control panel having an input unit to select one of a steam-using operation course and a superheated-steam-using operation course, wherein the input unit includes a course selecting unit for selecting a sanitary course enabling the steam generator to be activated only or a powerful sterilization course enabling both of the steam generator and the superheater (100, 200, 300) to be simultaneously activated, wherein the dishwasher is configured such that if a user selects the sanitary course, the steam is supplied at the defaulted steam time and for the defaulted steam period and if the user selects the powerful sterilization course, the superheated steam is supplied at the defaulted steam time and for the defaulted period, wherein the control panel further having an option selecting unit having a plurality of course selecting parts, the option selecting unit enabling the superheated steam to be additionally used for the course, wherein the user is able to select a different value to steam time and a different value for steam period, other than those stored as the default values of the steam time and steam period, by using the option selecting unit.