Component mounting method

A component mounting method comprising:

• while a component is accommodated within a component feeder, using a recognition device to recognize said component and thereby detect, as a component posture angle, a posture of said component relative to an ideal posture of said component;
• calculating a pre-holding rotational angle from a mounting angle and said component posture angle, with said mounting angle corresponding to a posture of said component, that said component is to exhibit when mounted on said object, relative to a basic posture of said component;
• rotating a component holding member by said pre-holding rotational angle in one direction from a reference posture of said component holding member to a rotated position;
• using said component holding member, while in said rotated position, to remove said component from said component feeder and hold said component;
• then
• rotating said component holding member, while holding said component, to said reference posture;
• and then
• mounting said component onto an object,
• wherein rotating said component holding member, by said pre-holding rotational angle, in said one direction from said reference posture of said component holding member to said rotated position comprises rotating said component holding member about an axis thereof by a driving device via a transfer member that causes an error to result in an amount that said component holding member is rotated only when said component holding member is rotated in a first direction, and does not cause an error to result in an amount that said component holding member is rotated when said component holding member is rotated in a second direction opposite to said first direction.