Lens barrel and imaging apparatus

A lens barrel comprising:

• a first lens holding frame that holds a first lens;
• a first protruding portion protruding from the first lens holding frame;
• a first motor configured to move the first lens holding frame in an optical axis direction;
• a second lens holding frame that holds a second lens;
• a second protruding portion protruding from the second lens holding frame;
• a second motor configured to move the second lens holding frame in the optical axis direction;
• and
• an outer barrel that (i) has a straight groove, which engages with the first protruding portion and the second protruding portion and extends in the optical axis direction, and (ii) is disposed further outward than the first lens holding frame and the second lens holding frame, wherein:
• the straight groove extends continuously between first and second ends in the optical axis direction;
• the first and second protruding portions are located within the straight groove between the first and second ends;
• and
• the first protruding portion and the second protruding portion (i) at least partially overlap each other in a circumferential direction about an optical axis and (ii) are in contact with each other in the circumferential direction.