A substrate treating apparatus is disclosed. The apparatus may include a housing including an upper body and a lower body coupled to each other to define a treatment space, the lower body being provided below the upper body, a supporting unit coupled to the upper body, the supporting unit supporting an edge of a substrate disposed in the treatment space, a fluid supplying unit configured to supply fluid into the treatment space, a sealing member provided between and in contact with the upper and lower bodies, the sealing member hermetically isolating the treatment space from an outer space, and an isolation plate installed between the sealing member and the supporting unit. The isolation plate may be provided to face the sealing member.