The paper discusses the results of a joint work of the Central Office of Measures in the Republic of Poland and the Military University of Technology in Warsaw within the framework of the project “Measurement Consistency in Electromagnetic Power Measurements in the Sub-THz Band”. The main problems in the study of electromagnetic radiation power in the terahertz range using a bolometric detector are considered. The design and parameters of the measuring system based on the use of a resistive bolometric detector, own signal amplifier, and measuring converter, which were designed and implemented at the Central Office of Measures in the Republic of Poland, are described. The results of metrological traceability to the SI units are presented. This paper is dedicated to expanding measurement capabilities of the bolometric detector based on a highly stable and inexpensive measuring system in the terahertz range. As a result of the joint work, a measuring system characterized by high parameter stability and a gain of more than 20 000 V/V was developed and tested.