Abstract: The invention relates to an indentation apparatus (1) comprising a force frame (13) and a positioning frame (14). An indentation tool (5) is pressed into a work piece (7) in order to master a mould. The work piece (7) is supported by the base (6). An actuator (2) is mounted in the force frame (13). The actuator (2) and the indentation tool head (4) are connected with a rod (3). The rod (3) is fixed with flexible (swivel) joints (15) to said indentation tool (4) and said actuator (2) in order to physically decouple said force frame (13) and said positioning frame (14) from forces. Also a force sensor (9) is installed between the indentation tool (4) and the positioning frame (14). In order to keep the positioning frame unloaded, the balance force delivered by said force frame actuator (2) should be approximately equal to the indentation force. The signal of the force sensor (9) is interpreted by control electronics (10).