A threaded joint for pipes, comprising a pin provided with a male thread portion , which is a male tapered thread, at one end of a first pipe, and a box provided with a female thread portion , which is a female tapered thread to be screwed with the male thread portion , at one end of a second pipe, wherein the female thread portion has a plurality of thread grooves, each of the plurality of thread grooves has a corner portion on a load flank side and a corner portion on a stabbing flank side on a thread bottom side, a flank angle of the plurality of thread grooves , which is defined as positive when the flank surface is inclined toward the thread and negative when it is inclined toward the opposite side of the thread, with respect to a straight line perpendicular to a pipe axis, satisfies the following conditions (a) and (b): (a) an angle of the stabbing flank is +5 to +40 degrees with respect to a straight line perpendicular to the pipe axis; and (b) an angle of the load flank is -10 to 0 degrees with respect to a straight line perpendicular to the pipe axis, a corner portion on a load flank side of a first thread groove , which is the thread groove farthest from an end of the box among the plurality of thread grooves , comprises a first arc portion that is directly connected to a load flank and has a first curvature radius (R1), and a second arc portion that is directly or indirectly connected to the first arc portion and has a second curvature radius (R2), an angle θ of the first arc portion , which is defined as an angle between a straight line "a" parallel to the pipe axis and a radius "r" at the end of the first arc portion on the opposite side of the load flank, is 50 ° or more and 75 ° or less, and a ratio of curvature radius, which is a ratio of the second curvature radius (R2) to the first curvature radius (R1), is 3 or more. a pin provided with a male thread portion , which is a male tapered thread, at one end of a first pipe, and a box provided with a female thread portion , which is a female tapered thread to be screwed with the male thread portion , at one end of a second pipe, wherein the female thread portion has a plurality of thread grooves, each of the plurality of thread grooves has a corner portion on a load flank side and a corner portion on a stabbing flank side on a thread bottom side, a flank angle of the plurality of thread grooves , which is defined as positive when the flank surface is inclined toward the thread and negative when it is inclined toward the opposite side of the thread, with respect to a straight line perpendicular to a pipe axis, satisfies the following conditions (a) and (b): (a) an angle of the stabbing flank is +5 to +40 degrees with respect to a straight line perpendicular to the pipe axis; and (b) an angle of the load flank is -10 to 0 degrees with respect to a straight line perpendicular to the pipe axis, (a) an angle of the stabbing flank is +5 to +40 degrees with respect to a straight line perpendicular to the pipe axis; and (b) an angle of the load flank is -10 to 0 degrees with respect to a straight line perpendicular to the pipe axis, a corner portion on a load flank side of a first thread groove , which is the thread groove farthest from an end of the box among the plurality of thread grooves , comprises a first arc portion that is directly connected to a load flank and has a first curvature radius (R1), and a second arc portion that is directly or indirectly connected to the first arc portion and has a second curvature radius (R2), an angle θ of the first arc portion , which is defined as an angle between a straight line "a" parallel to the pipe axis and a radius "r" at the end of the first arc portion on the opposite side of the load flank, is 50 ° or more and 75 ° or less, and a ratio of curvature radius, which is a ratio of the second curvature radius (R2) to the first curvature radius (R1), is 3 or more. <EOS>