A branch blood vessel insertion catheter to be inserted into a branch blood vessel branching from a first blood vessel by passing said catheter through a blood vessel branch from said first blood vessel; wherein said catheter has a catheter body having a lumen penetrating therethrough from a distal end of said catheter body to a proximal end thereof to allow a guide wire to be inserted therethrough; said catheter body has an inner layer, a wire-wound reinforcing member provided on an outer surface of said inner layer, and an outer layer covering both said inner layer and said reinforcing member; and said catheter body has an outer diameter of a distal end portion being not more than 0.7 mm, a first physical property change point located at a position apart from a distal end of said catheter at a distance of 3.0 to 7.0 mm and having an axial length of not more than 2.0 mm; and a rigidity of a portion of said catheter body located proximally from said first physical property change point is set higher than that of a portion of said catheter body located distally from said first physical property change point; said catheter body has a second physical property change point, said catheter body has a rigidity of a portion of said catheter body located proximally from said second physical property change point is set higher than that of a portion of said catheter body located distally therefrom, said second physical property change point is a diameter-increased part located at a position apart from said distal end of said catheter at a distance of 12.0 to 18.0 mm or a position apart from said first physical property change point at a distance of 7.0 to 13.0 mm, said catheter body has an outer diameter difference of 0.02 to 0.05 mm between a portion of said catheter body located distally from said second physical property change point and a portion of said catheter body located proximally therefrom, and an axial length of said second physical property change point is not more than 2.0 mm. wherein said catheter has a catheter body having a lumen penetrating therethrough from a distal end of said catheter body to a proximal end thereof to allow a guide wire to be inserted therethrough; said catheter body has an inner layer, a wire-wound reinforcing member provided on an outer surface of said inner layer, and an outer layer covering both said inner layer and said reinforcing member; and said catheter body has an outer diameter of a distal end portion being not more than 0.7 mm, a first physical property change point located at a position apart from a distal end of said catheter at a distance of 3.0 to 7.0 mm and having an axial length of not more than 2.0 mm; and a rigidity of a portion of said catheter body located proximally from said first physical property change point is set higher than that of a portion of said catheter body located distally from said first physical property change point; said catheter body has a second physical property change point, said catheter body has a rigidity of a portion of said catheter body located proximally from said second physical property change point is set higher than that of a portion of said catheter body located distally therefrom, said second physical property change point is a diameter-increased part located at a position apart from said distal end of said catheter at a distance of 12.0 to 18.0 mm or a position apart from said first physical property change point at a distance of 7.0 to 13.0 mm, said catheter body has an outer diameter difference of 0.02 to 0.05 mm between a portion of said catheter body located distally from said second physical property change point and a portion of said catheter body located proximally therefrom, and an axial length of said second physical property change point is not more than 2.0 mm.