The　gage　cutter　is　the　key　component　in　a　tunnel　boring　machine　(TBM);　this　part　affects　the　machine＇s　cutting　efficiency　and　maintains　the　tunnel　diameter.　In　this　study,　a　series　of　rock　cutting　tests　with　different　parameters　(cutting　spacing,　penetration　depth,　and　installation　angle)　is　conducted　using　the　mechanical　rock　fragmentation　experimental　platform　of　Beijing　University　of　Technology　to　study　the　influences　of　these　parameters　on　the　rock-breaking　performance　of　a　TBM　gage　cutter.　During　the　tests,　the　triaxial　cutting　forces　and　rock　chips　are　collected　and　analyzed.　The　test　results　show　that　the　average　normal　force　of　the　cutter　will　decrease　with　the　installation　angle　increasing　at　the　same　penetration　depth　and　cutting　spacing,　but　the　average　rolling　force　has　the　opposite　change　tendency.　The　side　force　is　influenced　by　the　installation　angle　significantly.　The　side　force　of　the　gage　cutter　plays　a　more　important　role　in　the　rock　fragmentation　than　does　the　side　force　of　the　normal　cutter.　Moreover,　the　cutting　efficiency　of　the　normal　cutter　is　higher　than　that　of　the　gage　cutter.　An　inclined　disc　cutter　is　more　conducive　to　producing　rock　chips　under　a　large　cutting　spacing　than　is　a　vertical　disc　cutter,　and　the　optimal　cutting　spacing　under　different　installation　angles　is　different.　This　study　can　provide　a　reference　for　TBM　gage　cutter　design　and　TBM　operation　parameter　optimization.　©　Published　under　licence　by　IOP　Publishing　Ltd.