Abstract: A robot arm structure for a carrying robot is capable of carrying a load in a wide range under restrictions on robot arm motions. A second arm 38 is joined to an upper link 35, a third arm 39 is joined to the second arm 38, and a fourth arm 40 is joined to the third arm 39. A holding unit mounted on the fourth arm 40 can be moved in a wide range through the angular displacement of the second arm 38 to the fourth arm 40 even in a state where a first arm 36 is maintained at a predetermined position relative to a bed 33. Thus a load can be moved in a wide range.