Support arm

A support arm comprising:

• a first joint part supported by a base;
• a second joint part arranged away from said first joint part;
• a first parallel link arranged between said first joint part and said second joint part and coupled pivotally to said first joint part and said second joint part;
• and
• a self-weight compensation device producing a force that cancels a force of gravity acting on said first parallel link,
• said first parallel link having a first shaft and a second shaft arranged in parallel to each other with spacing, the spacing being changed with a pivoting movement of said first parallel link,
• said first shaft and said second shaft being arranged offset with respect to each other in a direction of an axis on which said first parallel link is pivoted,
• when said first parallel link is positioned to extend laterally from said first joint part, said first shaft being located above said second shaft,
• said second shaft having a thickness greater than the thickness of said first shaft, and
• a wiring line extending from said first joint part toward said second joint part being fixed to said second shaft.