Abstract: A diagonal type MHD generator channel frame element, having a polygonal configuration which is preferably rectangular, is formed from two different pairs of pre-formed hollow bars, one of the pairs serving as the electrode members, while the other pair serves as the electrode-interconnecting diagonal members. The electrode members have cross-sectional profiles corresponding to that of a parallelogram while the diagonal members have rectangular cross-sectional profiles. Pre-formed coolant passages are defined within the members in an entirely enclosed manner, and the cross-sectional profiles of the passages correspond to those of the members within which the passages are defined.