Medical arm device

A medical arm device comprising:

• a first arm part including a tip part that supports a medical instrument;
• a second arm part that supports the first arm part having at least two rotation axes enabling horizontal planar rotation and an inter-axis distance changing mechanism configured to change a distance between the two rotation axes, wherein the second arm part includes
• a first link,
• a first joint part having a degree of freedom around a first rotation axis of the at least two rotation axes at a tip of the first link,
• a second link horizontally attached to the tip of the first link via the first joint part, and
• a second joint part having a degree of freedom around a second rotation axis of the at least two rotation axes at a tip of the second link,
• the second link includes the inter-axis distance changing mechanism, wherein the second link is configured to expand and contract to change the distance between the first rotation axis and the second rotation axis, and
• the first arm part is supported via the second joint part;
• and
• an intermediate part that connects the first arm part and the second arm part, the intermediate part having a rotation axis orthogonal to the at least two rotation axes,
• wherein the tip part includes a structure in which the rotation axis around a longitudinal axis of the medical instrument, a yaw axis, and a pitch axis are disposed in order from a most distal part and are directly connected via joint members without an interposed link.