There are growing expectations that wearable devices will provide feedback on the health status of older adults, which can be used to raise their awareness of voluntary health maintenance and appropriate intervention by their supporters. On the other hand, older adults have many difficulties in the use of information devices, and at the same time, it is difficult to find out their own ways to use ICT devices or values of their usage, for older adults. In order to investigate those possibilities, a three-week continuous usability testing experiment was conducted for 8 healthy older adults using a wristband-type health smartwatch (Fitbit Sense). As a result, all participants were able to use the device continuously for three weeks, at least in the circumstances where we the testers set up. Even though their activity indexes were not changed significantly, there were some focused interests by older adults in their activities and/or daily reports; interests to the sleep evaluations, motivations to physical activities, and awareness of time and executing activities. Importance to design for being able to set-up their using circumstances by older adults themselves, and ways to sense and keep users’ interests or their values to use will be the keys to wearable information devices can be tools for older adults.