In this study, the effects of antenna types and output powers on charging times of RF energy harvesting circuit were measured and analyzed in detail. A measurement system which consisting of a signal generator, an RF energy harvesting circuit, antennas and other devices was installed for receiving the measurement samples. According to the measurement results, the shortest charging time was obtained as 0.58 s at a distance of 20 cm, when 6.1 dBi antenna was connected to the RF energy harvesting circuit and the output power of the signal generator was set to 17 dBm. In addition to that, the longest charging time was evaluated as 25.01 s at a distance of 60 cm, when 1 dBi antenna was connected to the RF energy harvesting circuit and the output power of the signal generator was adjust to 14 dBm. As a result, it was determined that increasing of antenna gains and output powers and shortening of distances between signal generator and RF energy harvesting circuit decreased the charging times of the RF energy harvesting circuit in this study.