The diploma thesis deals with the measurement of electromagnetic fields by the meter NARDA NBM 550. The aim of the paper is to introduce the possibilities of measurement of the electromagnetic field by this device, to study the feasibility of communication with computer, to create control program and to check its functionality. A description of the electromagnetic field properties is followed by the identification of the device main functions. Additionally, the operating program is described together with the draft of measuring workplace with its realization. The results of probationary measurements are presented in the end of the thesis.