Provided is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing device, the glass being an amorphous glass that contains at least Li.sub.2O, in which a total content of Na.sub.2O and K.sub.2O is 0 mol % or more and 6.0 mol % or less, a B.sub.2O.sub.3 content is 0 mol % or more and 10.0 mol % or less, and a CaO content is 0 mol % or more and 1.0 mol % or less.