A robotic arm includes a first driving source and a second driving source mounted on a base frame, a first transmission link driven by the first driving source to turn around a first axis, a second transmission link driven by the second driving source to turn around a second axis that is parallel to the first axis, a third transmission link pivoted to the first transmission link, a first driven link pivoted to the second transmission link, a second driven link pivotally coupled between the first driven link and the base frame, a third driven link pivotally connected with the first and second driven link, and a fourth driven link pivotally coupled between the third driven link and the third transmission link. Thus, the robotic arm of the invention has a compact size and can achieve multi-degree of freedom motion.