The purpose of this paper is to evaluate office workers' productivity in terms of the indoor environment and their activities. The surveyed office was an engineering laboratory designed for high energy conservation. In this study, field measurements in the office and a questionnaire survey to the workers were conducted to reveal, through study of the workers' activities, the relationship between the workers' creativity and the workplace environments. The results indicated that the indoor environment was maintained at good levels. Also satisfaction of studied building was higher than the building before relocation. However, some workers were dissatisfied with certain elements of the environment. Further consideration of these points could lead to improvements in productivity. Communication was observed to occur not only at designated communication spaces but also around the workers' desks. Additionally, workers requested suitable environments for each of their behaviors.