A lithium ion conducting material includes a sulfide-based solid electrolyte material that contains Li, an element that belongs to group 13 to group 15 and S, and that contains an MSx unit, wherein M is an element that belongs to group 13 to group 15, S is a sulfur element, and x is the maximum number of S atoms that can be bonded with M, and an inhibitor that is in contact with the sulfide-based solid electrolyte material and that contains a metal element having an ionization tendency lower than that of hydrogen.