Disclosed is a substrate treating apparatus that performs a cleaning treatment on substrates. A treating block includes a plurality of treating units in an upper and lower stages, respectively. The treating block includes a front face cleaning unit and a back face cleaning unit, each being at least one in number, in the upper stage. The treating block includes at least one tower unit including the front face cleaning unit and the back face cleaning unit, each being at least one in number, in the lower stage. Moreover, a transportation block is provided that includes a center robot in each of the upper and lower stages.