Abstract. This paper describes how we recognize activities of daily living (ADLs) with our designed sensor device, which is equipped with heterogeneous sensors such as a camera, a microphone, and an accelerometer and attached to a user’s wrist. Specifically, capturing a space around the user’s hand by employing the camera on the wrist mounted device enables us to recognize ADLs that involve the manual use of objects such as making tea or coffee and watering plant. Existing wearable sensor devices equipped only with a microphone and an accelerometer cannot recognize these ADLs without object embedded sensors. We also propose an ADL recognition method that takes privacy issues into account because the camera and microphone can capture aspects of a user’s private life. We confirmed experimentally that the incorporation of a camera could significantly improve the accuracy of ADL recognition. Key words: Wearable sensors; Recognizing daily activities; Experiment