There are provided a puncture assisting device and a puncture device set which enable a drug to be easily and subcutaneously injected into a skin of an elbow joint stretching portion at an elbow by oneself. [Solution] A puncture assisting device (2) has a pair of plate-like pinching portions (13, 14) that face each other, and that are combined with each other so as to be openable and closeable, a biasing portion (15) that biases the pair of pinching portions (13, 14) in a mutually closing direction, a pair of nipping portions for opening (16, 17) that can operate the pair of pinching portions (13, 14) in a mutually opening direction, and a rod insertion portion (23) that is disposed between the pair of pinching portions (13, 14), and into which a rod portion (4) for widening a gap between the pair of pinching portions (13, 14) is inserted. A puncture device set (1) has the above-described puncture assisting device (2) and a syringe (3) in which the road portion (4) is disposed in a plunger (5).
