Turbine blade and steam turbine including the same

A turbine blade, comprising:

• an airfoil portion having a pressure surface and a suction surface each of which extends between a leading edge and a trailing edge;
• and
• a platform including an end wall to which a base-end portion of the airfoil portion is connected,
• wherein the end wall includes:
• a concave portion on suction surface disposed at least in a region of suction surface of the end wall;
• and
• a convex portion on pressure surface disposed at least in a region of pressure surface of the end wall,
• wherein the concave portion on suction surface has a bottom point located on an axially upstream side of a tangent point on the suction surface, the suction surface having a tangential line extending in an axial direction through the tangent point,
• wherein the end wall has at least one contour line on the concave portion on suction surface, the at least one contour line having a normal line on an intersection point between the at least one contour line and the suction surface such that a normal vector having a negative gradient along the normal line is directed toward the airfoil portion, and
• wherein the convex portion on pressure surface has a peak point located on an axially downstream side of the tangent point.