A method of production of a joint, the joint comprising: a base part, a pair of side parts respectively extending from two end parts of the base part in a first direction to the same side of a second direction vertical to the first direction and formed with fastening holes at center parts in a third direction vertical to both of the first direction and second direction, and a closed part formed between the pair of side parts as an extended region of the base part and the pair of side parts at least at one end part in the third direction, wherein a thickness t1 of the base part and a thickness t2 of the closed part satisfy the relationship t 2 > t 1 the method comprising: a blank bending step of bending at least one end part in the third direction of a blank comprised of a metal sheet to one side in the second direction to form an intermediate member of an upside down L-shape or upside down U-shape viewed from the side, wherein the blank is bended using shrink-flanging, and a joint shaping step of using press-forming die comprising a die provided with a pad for pressing the intermediate member, a punch arranged facing the die and provided with an inner pad supported to be able to move in a clamping direction, and an out-of-plane deformation suppressing tool of the closed part arranged facing a side surface of the punch so as to bend the two end parts of the intermediate member in the first direction to the one side of the second direction. a base part, a pair of side parts respectively extending from two end parts of the base part in a first direction to the same side of a second direction vertical to the first direction and formed with fastening holes at center parts in a third direction vertical to both of the first direction and second direction, and a closed part formed between the pair of side parts as an extended region of the base part and the pair of side parts at least at one end part in the third direction, wherein a thickness t1 of the base part and a thickness t2 of the closed part satisfy the relationship t 2 > t 1 the method comprising: a blank bending step of bending at least one end part in the third direction of a blank comprised of a metal sheet to one side in the second direction to form an intermediate member of an upside down L-shape or upside down U-shape viewed from the side, wherein the blank is bended using shrink-flanging, and a joint shaping step of using press-forming die comprising a die provided with a pad for pressing the intermediate member, a punch arranged facing the die and provided with an inner pad supported to be able to move in a clamping direction, and an out-of-plane deformation suppressing tool of the closed part arranged facing a side surface of the punch so as to bend the two end parts of the intermediate member in the first direction to the one side of the second direction. a blank bending step of bending at least one end part in the third direction of a blank comprised of a metal sheet to one side in the second direction to form an intermediate member of an upside down L-shape or upside down U-shape viewed from the side, wherein the blank is bended using shrink-flanging, and a joint shaping step of using press-forming die comprising a die provided with a pad for pressing the intermediate member, a punch arranged facing the die and provided with an inner pad supported to be able to move in a clamping direction, and an out-of-plane deformation suppressing tool of the closed part arranged facing a side surface of the punch so as to bend the two end parts of the intermediate member in the first direction to the one side of the second direction.