The aim of this research was the development and verification of the local muscular load measuring methodology as a valid and recognized measurement in order to subsequently strengthen injury prevention of occupational diseases among workers of both manufacturing and non-manufacturing companies. A milestone in the project was construction of a measuring device to obtain data for evaluating local muscular load with the use of force measurement, frequency of movements and positions and a device called datalogger. This measuring device was then tested and its functionality has been successfully proved in 40 measurements in both manufacturing and non-manufacturing enterprises. The reason for the development of this equipment was especially a requirement to learn the load (force generation) of the individual fingers when operators work, implemented by different grips, e. g. tridigital, pentadigital and so on. Such quantification is not possible with the current EMG method. The developed equipment had to be validated with existing certified methodology called electromyography, which allows only summative evaluation. The results of correlations of both measurements while evaluating the local muscular load are analyzed in this article. The aim of this paper is also to describe how the new device was developed and tested: the Datalogger for measuring local muscular load and its advantages and limitations. Based on the defense carried out, the Industrial Property Office subsequently issued a letters patent for the invention with a number PV 2015-820 earlier this year. The invention relates to an ergonomic device developed for monitoring of local muscular load, and is especially useful in workplaces where there is increased stress, particularly stress on your hands when multiple / repetitive movements, often involving spending increased muscle strength. Measurements can also be made for operators wearing different preservative gloves commonly used in practice. In this article the authors will introduce not only new patented apparatus itself, but a new methodology for local muscular load measuring with the datalogger as well.