Optical device and image pickup system

An optical device comprising:

• a movable member configured to support an optical element and to be movable in a direction including a component perpendicular to an optical axis;
• a fixed member configured to support the movable member;
• first and second driving units configured to move the movable member in directions different from each other;
• and
• a flexible substrate connected to the first and second driving units,
• wherein the flexible substrate includes first and second curved parts connecting the movable member and the fixed member,
• wherein the first and second curved parts are arranged inside a circle that is centered on the optical axis and circumscribes the first and second driving units when viewed from an optical axis direction, and
• wherein, when viewed from the optical axis direction, a midpoint between a point of action of a first reaction force generated when the movable member moves at the first curved part and a point of action of a second reaction force generated when the movable member moves at the second curved part is located inside a triangle connecting the optical axis and respective centers of the first and second driving units.