Abstract: A gas turbine cooled blade is constructed without an increase in the number of parts or time requirements, in which seal air is maintained at a lower temperature with the heat exchange rate being suppressed, and the heat transfer rate of the cooling medium in cooling passage is enhanced. A plurality of cooling passages (A, B, C, D, E) is provided in a blade, and the first row cooling passage (A) is covered at the blade inner and outer peripheries and communicates with the second row cooling passage (B) through communication holes (6) and with the main flow gas path through film cooling holes (7). The second row cooling passage (B) communicates with the blade inner peripheral cavity (10) to form a seal air supply passage. A plurality of ribs (31) are disposed on the inner wall of cooling passage (22) with a predetermined pitch (P).