There are few studies of the therapeutic effects of long-term corset wearing in patients with chronic low back pain. The aim of this study was to evaluate the effects of long-term corset wearing on chronic low back pain and to examine the myoelectrical activities of the paravertebral muscles. Forty subjects with chronic low back pain were enrolled and randomly divided into two groups: a group wearing corsets for 6 months (CW) group and a group not wearing corsets (NW). The treatment effects were measured using the Japanese Orthopaedic Association (JOA) score. Muscle endurance was evaluated during the Biering-Sorensen test (S-test), and the degree of muscle fatigue was evaluated by the change in percent mean power frequency (%MPF) of the paravertebral muscles. Corset treatment for chronic low back pain improved low back pain and increased muscle endurance for a short period of time. Paravertebral muscle fatigue was not increased by long-term corset wearing for chronic low back pain, and weakening of the paravertebral muscles was not observed up to 6 months after the start of corset wearing.