[Purpose] We tested the reliability and validity of the Japanese version of the Short Questionnaire to Assess Health-enhancing Physical Activity scale in asymptomatic older adults and sought to confirm discriminator validity in women with osteoarthritis. [Subjects] The participants included an asymptomatic comparison group (men and women) and women with knee or hip osteoarthritis. [Methods] The test-retest method was used to assess reliability. The International Physical Activity Questionnaire was chosen to assess criterion-related validity. Discriminator validity was assessed by comparing the asymptomatic and osteoarthritis groups. [Results] Mean age for the asymptomatic groups was 63 ± 6 years for men (n = 23) and 61 ± 7 years for women (n = 51), and it was 63 ± 9 years for the osteoarthritis group (n = 32). The total score and scores for all items, except for heavy housework items, were significantly correlated with the retest. Criterion-related validity showed significantly weak to moderate correlations between the respective scale categories. For discriminator validity, the total scores and scores for bicycle commuting, light housework, and three leisure items differed significantly between the asymptomatic and osteoarthritis groups. [Conclusion] The Short Questionnaire to Assess Health-enhancing Physical Activity scale is a reliable and valid measure in asymptomatic older adults, and can discriminate between osteoarthritic and asymptomatic women.