Disclosure relates to a cooking appliance. The cooking appliance may include a casing (100, 200) having a cavity (S1) and an electric chamber (S2) therein, and a door (300) opening and closing the cavity (S 1). In addition, a tank housing (460) storing a water tank (450) therein may be disposed in the electric chamber (S2). The tank housing (460) may have a tank chamber (450a) open towards a tank entrance (424) of a front housing (420). At this point, a front surface (462) of the tank housing (460) may be in close contact with a rear surface of the front housing (420), and the tank chamber (450a) may be connected to the tank entrance (424). As described above, when the tank housing (460) and the front housing (420) are in close contact with each other, leakage of water or inflow of foreign substances through a gap between the two components can be prevented.