A clip apparatus for ligaturing a living tissue includes a clip unit (14) provided removably at a distal end (10a) of an insertion part (10) inserted into a forceps channel of an endoscope, and an operating part (16) for the unit, extending in an passage (10c) of the insertion part. The unit has a clip holder (18) in an opening of the passage (10c) and a passage (18a) for elastically opening/closing of a clip (12), an engaging portion (20) to be opened elastically around the passage (18a) when the holder projects from the passage (10c), and longitudinally engaged with the distal end of the insertion part, and a structure (24) preventing excessive opening of the engaging portion when a member (22) connected to the clip and the operating part and moving in the passage (18a) is broken at a breakable portion (22a) by a pulling force from the operating part.