Objective: The purpose of this study is to investigate the benefit of LIPUS after Tibial Condylar Valgus Osteotomy (TCVO) for the osteoarthritis of the knee joint. Materials and Methods: This is retrospective study and the population of the study is 12 cases after TCVO with same locking plate and same artificial bone graft. Seven cases were treated LIPUS after TCVO (L group), and five cases were no LIPUS (NL group). Comparison was made of the period until bone fusion in L group and the NL group. The judgement of bone fusion was that the gap of the most proximal part of the osteotomy is no longer visible in the simple X-ray image. Results: The average of age was 63 (58–69) year old in L group, and 67 (59–76) year old in NL group. There was no significant difference in age between L group and the NL group. The average of the time of bone fusion was 73.6 (62–85) days in L group, and 95.0 (84–114) days in NL group. There were significant differences in the time of bone fusion between L group and the NL group (P < 0.05: Mann Whitney U test). Discussion: Usefulness of LIPUS after TCVO has been suggested in this study, although there is a limit to having a small number of surveys. There is a variation in the gap of the osteotomy, the time of bone fusion may be different depending on the size of the gap. There is a need to investigate the difference due to the treatment site of LIPUS.