Provided are gas turbine blades in which it is possible to simplify the formation of cooling channels provided inside the turbine blades while simultaneously avoiding loss of turbine blade strength and rigidity due to forming of the cooling channels. In a gas turbine blade (41), cooling channels (410) provided in the interior thereof include a plurality of straight channel-like base-side elongated holes (401a) that extend in a longitudinal direction at a base side of the turbine blade (41), a plurality of straight channel-like tip-side elongated holes (410b) that extend in a longitudinal direction at a tip side of the turbine blade (41), and a plurality of communicating hollow portions (410c) that are interposed at connection portions between the two types of elongated holes (410a, 410b) to individually allow the two types of elongated holes (410a, 410b) to communicate with each other and that have larger cross-sectional areas than the channel cross-sectional areas of both elongated holes (410a, 410b). In addition, the communicating hollow portions (410c) are formed so as to match the position of a platform portion (413) of the turbine blade (41).