Hot stamping formed article and method and device for manufacturing hot stamping formed article

A hot-stamping formed article made of steel,

• wherein the hot-stamping formed article has at least one of a tensile strength of 1200 MPa or more and a martensitic steel structure and includes a first portion, a corner portion, and a second portion, which are sequentially continuous from one end portion to an other end portion in a longitudinal direction,
• each of the first portion, the corner portion, and the second portion includes a top sheet and two vertical walls connected to the top sheet continuously when viewed in a cross section perpendicular to the longitudinal direction, wherein the two vertical walls include an outer vertical wall located on an outer peripheral side of the corner portion and an inner vertical wall located on an inner peripheral side of the corner portion,
• the second portion includes a first outwardly-extending flange adjacent to the outer vertical wall, and
• the corner portion includes
• a vertical flange extending from the outer vertical wall of the first portion,
• a second outwardly-extending flange adjacent to the outer vertical wall, and
• a transition portion in which the vertical flange and the second outwardly-extending flange are continuous.