An ink jet recording head unit for performing a recording operation by discharging ink is desclosed. The ink jet recording head unit includes an ink jet head portion having an ink passage communicated with a discharge port for discharging ink and a substrate having an energy generating element for causing energy for discharging ink to act on ink present in the ink passage, the ink being supplied through an ink receiving port of a connecting portion; and an ink supply member having a connecting portion to be connected to the ink jet head portion so as to supply ink to the ink jet head portion via the connecting portion. At least one of the connecting portion of the ink jet head portion and the connecting portion of the ink supply member has a projection portion at a position at which it comes in contact with the corresponding connection port so that one connecting portion is respectively connected to a corresponding connecting portion by deforming and bringing the projection portion into contact with the connecting portions.