19.5 kHz complex vibration systems using various complex transverse vibration welding tips vibrating in rotating circular to elliptical locus which are exchangeable by a connecting bolt have been proved very useful for various same and dissimilar welding specimens. But, higher frequency systems are desired to improve welding characteristics for smaller and light weight welding specimens. To decrease required vibration amplitude and vibration damage of welding specimen, 27 kHz and 40 kHz ultrasonic complex vibration welding systems using various exchangeable welding tips were designed newly. Higher frequency complex vibration systems are effective for welding of small and light weight specimens. Required vibration amplitudes for 27 kHz and 40 kHz welding system are 62% and 34% compared with 19.5 kHz system. 27 kHz and 40 kHz diagonal slit one wave-length longitudinal vibration mode longitudinal to torsional complex vibration converters have sufficient working space for complex vibration welding system. The 27 kHz and 40 kHz diagonal slit converter developed are 38 mm and 30 mm in diameter and have four installing positions at the free edge for various welding tip.