A knife holder apparatus for a cut pile tufting machine including a knife block fixed to a depending mast which is slidably mounted within a corresponding slot in the knife bar and a wedge clamp member adapted to clamp or lock the knife bar carrying a plurality of knives in an operative position relative to the knife bar in which the knives cooperatively engage their corresponding looper hooks. The knife holder apparatus supports the knives at their predetermined tension and pitch angles relative to the looper hooks and in a manner in which the knife holder module and knives may be easily and quickly removed and replaced.