A robotic arm assembly includes a first segment, a second segment, a first driving device, a first transmission mechanism, a second driving device, and a second transmission mechanism. The second segment is rotatably connected to the first segment. The first driving device drives the second segment to rotate about a first axis relative to the first segment via the first transmission mechanism. The second transmission mechanism includes a first bevel gear and a second bevel gear meshed with the first bevel gear. An output shaft is fixed to the second bevel gear, and the output shaft is capable of rotating about a second axis. Each of the second segment, the output shaft, and the second bevel gear defines a guiding hole, and the guiding holes are aligned in the second axis.