Provided are a chalcogen compound having ovonic threshold switching characteristics, and a switching device, a semiconductor device, and/or a semiconductor apparatus which include the chalcogen compound. The chalcogen compound includes five or more elements and may have stable switching characteristics with a low off-current value (leakage current value). The chalcogen compound includes: selenium (Se) and tellurium (Te); a first element comprising at least one of indium (In), aluminum (Al), strontium (Sr), and calcium (Ca); and a second element including germanium (Ge) and/or tin (Sn), and may further include at least one of arsenic (As), antimony (Sb), and bismuth (Bi).