The tensile strength of rocks is of great importance in many engineering and geophysical applications. Considered a key parameter in rock mechanics projects, its determination in the laboratory has been discussed for years by many researchers with two strands: the direct tensile test, considered the ideal and most realistic, has its credibility compromised due to the possibility of altering the final result involving its poor execution, on the other hand, the indirect tests, due to practicality, spread around the world, however, a scientific community does not ignore such deficiencies involving the results. Thus, from this scenario, this work brings the construction of a compression to tension load converter (CTC), which allows the determination of the tensile strength of the rocks in a direct and reliable way. A numerical analysis was necessary to determine the ideal geometry of the specimen. Uniaxial compression tests, brazilian tests and direct tensile strength tests (CTC), were perfomed in syenogranites from Cachoeiro de Itapemirim-ES, in order to compare the results obtained with the literature data. The results showed that, the load converter has a good performance according to the proposed objectives, the samples broke due to pure tensile in the center of the halter-shaped specimen, and as evidenced, for all tested rock samples, to the direct tensile strength are clearly lower than the indirect tensile strength.