In　this　work,　more　than　130　line　peaks　in　electron　spin　resonance　(ESR)　spectra　have　been　discovered　of　the　laser　material　MgF2　crystal　in　room-temperature　experiments.　A　sample　is　cut　from　the　shoulder　part　of　the　MgF2　crystal,　and　another　is　from　the　MgF2:CO　crystal.　The　samples　were　not　treated　by　any　irradiation.　The　same　anisotropic　ESR　spectra　of　the　two　samples　indicate　that　the　dopant　Co2+　introduces　defects　which　induce　the　same　multinuclear　free　radicals　as　in　dislocations　in　the　sample　of　MgF2.　These　paramagnetic　solid　multinuclear　free　radicals　show　good　stability,　and　their　ESR　spectra　are　found　to　be　anisotropic.　ESR　signals　are　derived　from　three　different　types　of　multinuclear　free　radicals　from　a　tentative　simulation　analysis.　When　the　direction　of　the　applied　magnetic　field　is　along　the　[100]　or　[010]　orientation　of　the　crystal,　the　magnetic　field　at　which　the　ESR　signals　are　detected　ranges　from　0.2294T　to　0.4654T　and　the　width　of　this　range　is　0.2362T　(corresponding　to　an　energy　band　of　0.233eV);　the　most　narrow　peak　in　the　ESR　spectra　has　a　width　Delta　H　about　1.28　X　10(-3)T.　This　width　Delta　H,　equivalent　to　the　energy　difference　of　two　neighbouring　levels,　is　very　small,　only　1.85　X　10(-7)eV　(or　1.46　X　10(-3)cm(-1)).　This　fact　indicates　that　the　ground　state　is　highly　degenerate,　and　splits　into　nearly　quasi-continuous　energy　levels　like　an　energy　band　in　an　applied　magnetic　field.　It　may　be　served　as　a　new　starting　point　of　solid　laser　exciter　frequency　modulation.