PURPOSE: To make no space between an angle member and an interior member, etc., by machining an interior angle part of a metal plate after the metal plate is machined into an approximately right-angled intermediate member, making the interior angle pat and an exterior angle part as an approximately right angle, and forming a recession-shaped relief section in the interior angle part.

CONSTITUTION: After a metal plate is machined into an approximately right- angled intermediate member, an interior angle part 102 is machined by means of a milling cutter to form a recession-shaped section 103. An angle member 1 that an angle α of the interior angle part 102 and an angle β of the exterior angle part 101 bringing one side 11 into contact with the outer side 12 respectively exhibit right angle is constituted. An internal wall 111 of the recession-shaped relief section 103 is positioned inside closer than virtual contact lines K and K on extension lines of each of insides 110 and 120 of both sides 11 and 12. According to the constitution, when the interior member, etc., are executed to the inside of the angle member 1, both members can be adhered tightly together.