Ergonomics and work safety can be developed by influence on all elements taking part in working process. Respecting the technical object (machine) as an element of working process, person can influence on the safety in every stage of its life cycle. However, the safety of machine can and should be developed on the stages of designing and producing. The most proper and effective ones are preactivities, therefore machine's designing stage is very important. During designing there is defining the most important features of machine and methods of its exploitation (developing of potential features which are important regarding the safety). On the stage of producing the activities are continuing by realization of the decisions and verification of machine's features (material conferment of supposed features). On the stage of exploitation of machine, the safety is controlled by such an influence on the process of its exploitation and operating, to not to exceed the proper risk level, created by the machine. The author maintains that the process of developing of machine's safety should begin before the designing, producing and researches. It will have the most gainful technical as well as economical effect. In the elaboration the theoretical basis of machine's safety modeling are formulated on the stage of laboring the conception. There are showed the principles of building and analysis of general model of machine's safety and defined: - terminology; - potential, important hazards, concerning the machine's exploitation; - principles of risk assessment and decreasing; - sources of requirements concerning the safety and ergonomics of regarding the safety and ergonomics of machine's exploitation; -principles of choice of machine's features, the most important regarding the safety and ergonomics of future real machine's exploitation; - principles of using the means of safety which should be provided on the stage of designing; - criterions of accepting the machines as safe. Model of safety of the machine, used in the next stage of creating the machine (in the stage of designing and building the prototype) should be the basis of such a designing and producing the particular units and all the machine, to make maximum possible the decreasing of a risk concerning the future exploitation of the real machine.