Computed tomography (CT) is widely used for follow-up of lung metastasis in patients due to soft tissue sarcoma (STS), the frequency of chest X-ray (CXR) is obviously reduced. This study verified the current status of diagnostic measures and the efficacy of CXR. A retrospective analysis of 18 patients that underwent surgery for lung metastasis due to STS was performed. The investigation compared the follow-up interval using CT after STS surgery, time from STS surgery to lung metastasis, tumor size of lung metastasis, detection rate with CXR, time from detection to surgery for lung metastasis, number of CT scans and follow-up interval using CT after detection of lung metastasis. The follow-up interval when using CT after STS surgery was 3.5 months (m). Time from STS surgery to lung metastasis was 34.3m. Tumor size of lung metastasis was 15 mm, and the detection rate by CXR was 66.7%. The time from detection to surgery for lung metastasis was 4.8m, the number of CT scans was 3.1, and the interval was markedly shortened to 1.6m. Follow-up should be performed by CXR if the tumor is detected by CXR. CT evaluation is required when the tumor size has increased, and prior to surgery for lung metastasis.