Abstract. Hexapod as a parallel robot is mechanism with changeable leg length. From 1950 onwards, parallel robots in a variety of different research and industrial purposes built and have been exploited.in this research, the free vibration analysis of machine tool set based on Stewart mechanisms with legs with the ability to change length and capable of machining complex parts with medium and small sizes have been studied. In earlier works, vibration analysis of hexapod table alone, without considering the structures of Machine tool was implemented. In the present study, body of machine tool as a vibration chain connected to the entire system is analyzed and free vibration analysis of Hexapod Machine tool set includes table and FP4M milling machine head as a complete vibration chain is studied. In order, vibration equations of Hexapod table and connected milling machine and tools is written and extraction program of natural frequencies of the structure in MATLAB software is written. Then in order to verify the theoretical work, modeling of the frame and Hexapod table set is done in the ANSYS software and the natural frequencies obtained were compared with the theoretical results of this software.