The present invention comprises: a fixed four-node link in which four links are joined together in a hinged fashion, comprising a fixed link of which the position is fixed, a connecting rod positioned on the opposite side of the first link, an input-side transmission link connecting the end on one side of the connecting rod and the first link, and an output-side transmission link positioned on the opposite side of the input-side transmission link； an input link part to which an actuator is attached, and which is joined in hinged fashion between the two ends of the input-side transmission link； and an output link part which is fixedly joined to the output-side transmission link and is rotated by means of the output-side transmission link, and the one-degree-of-freedom link device according to the present invention and the robot arm using the same can be used to allow easy attachment and detachment between link devices and achieve smooth action in a robot arm in accordance with what is desired.
