Suspension arm

A suspension arm that comprises a main body including a curved portion and having a closed section, the curved portion being curved along a longitudinal direction, a first attachment portion provided at one end of the main body in the longitudinal direction and including a first hole, and a second attachment portion provided at another end of the main body in the longitudinal direction and including a second hole, wherein

• the main body includes:
• an inner side wall that corresponds to an inner side of a curve of the curved portion;
• an outer side wall that corresponds to an outer side of the curve of the curved portion;
• a first side wall that connects one side edge of the inner side wall and one side edge of the outer side wall;
• and
• a second side wall that connects another side edge of the inner side wall and another side edge of the outer side wall and faces the first side wall,
• a thickness of the inner side wall is larger than a thickness of the outer side wall,
• in sectional view of the main body perpendicular to the longitudinal direction, each of a length of the first side wall and a length of the second side wall is longer than each of a length of the inner side wall and a length of the outer side wall, and
• a ratio of a height of the main body to a width of the main body is 2.0 to 4.0.