This invention aims to reduce the number of components and to identify easily when the tip of the needle 5 enters the epidural space without the identification device touching any medical instruments such as needles in the operation of epidural anesthesia. Means to solve the problem is that: an epidural space identification device to identify when a tip of a needle used for epidural anesthesia enters an epidural space that includes a barrel 2 formed in a cylindrical shape and communicatively connected to a needle 5 section, a plunger 3 formed in a cylindrical shape, retractably inserted into the barrel 2, and having an air hole 3e communicating with an inside of the plunger, and an expansible member 4 having an expansible part 4e provided at a front end part 3b of the plunger 3 and bulging inside of the plunger 3 with a positive pressure generated by pushing the plunger 3 while air discharge from a needle 5 side is regulated.
