This study proposes a method for indoor activity assessment by means of continuous and quantitative measure of personal physical and mental activity, basing on contents and contexture of location and behaviors. This article focused on development of an integrated wearable instrument which is capable of both indoor movements tracking and monitoring of concurrent psycho-physiologically indicated mental activity. A body-mounted inertial instrument utilizing accelerometers, gyros, and a bolometer was designed to obtain feature of three-dimensional indoor locomotive behaviors. Skin resistance change by electro-dermal activity was measured as an index of emotional arousal. Potential usefulness for assessing indoor pedestrian was demonstrated in a multi-story building.