Purpose The Tampa Scale for Kinesiophobia (TSK) has been used worldwide as a measure of kinesiophobia, but its factor structure in older Japanese adults after lumbar surgery is unknown. The purpose of this study was to fill this research gap by identifying the factors that comprise TSK in older Japanese adults after lumbar surgery. Patients and Methods Participants were older Japanese adults who had undergone surgery for lumbar spinal stenosis. Clinicodemographic data, TSK, intensity of low back pain and leg pain, dysesthesia (using an 11-point numerical rating scale), and HRQOL (using the EQ-5D-5L) were collected. After supplementing the missing values by the multiple assignment method, the hypothetical model of TSK was developed by categorical exploratory factor analysis (weighted least squares method, promax rotation). Confirmatory factor analysis (WLSMV method, promax rotation) was used to compare the hypothetical model and the traditional one-factor and two-factor models. Furthermore, we confirmed the relationship between factors extracted from the hypothetical model and HRQOL, pain, and dysesthesia. Results Questionnaires were mailed to 302 individuals, and responses were obtained from 211 (72.4±4.2 years [range: 65–88]; 115 men and 96 women; 804±343.1 [380–1531] days after surgery; 137 who had undergone decompression and fixation surgery, 74 who had undergone decompression surgery) (response rate: 69.9%). The hypothesized model consisted of “somatic focus,” “activity avoidance,” and “efficacy of physical activities,” all of which were highly consistent. The fit of the hypothetical model was slightly inferior to that of the traditional two-factor model, but the hypothetical model met the criteria for fit. Somatic focus in the hypothetical model was significantly associated with HRQOL, pain, and dysesthesia. Conclusion In older Japanese adults after lumbar surgery, the goodness of fit of the TSK model was maintained by adding efficacy of physical activities as a third factor to the traditional two factors.