Affords high-stability, high-safety lithium secondary batteries of high energy density and superlative charge/discharge cyclability, in which shorting due to the growth of dendrites from the metallic-lithium negative electrode is kept under control.A lithium secondary battery negative-electrode component material, formed by laminating onto a substrate a metallic lithium film and an inorganic solid-electrolyte film, the lithium secondary battery negative-electrode component material characterized in that the inorganic solid-electrolyte film incorporates lithium, phosphorous, sulfur, and oxygen, and is represented by the compositional formula noted below. aLibPcSdO(Li: lithium; P: phosphorous; S: sulfur; O: oxygen), wherein the ranges of the atomic fractions in the composition are: 0.20.ltoreq.a.ltoreq.0.45; 0.10.ltoreq.b.ltoreq.0.20; 0.35.ltoreq.c.ltoreq.0.60; 0.03.ltoreq.d.ltoreq.0.13; (a+b+c+d=1).