The purpose of this study was to develop the environmental sensitivity(ES) measurement instrument and to apply for middle school students. The questionnaire was developed to evaluate ES. The developed questionnaire consists of 15 items in 5 categories. Each item of the instrument was developed through the conceptional analysis of the definition of ES. The 5 categories included natural environment, activity at natural environment, artificial environment, environmental pollution, environmental destruction. Data for this study were collected from 397 middle school students including 46 environmental class and 351 non-environmental class students. It was found that the developed instrument to measure ES was valid and reliable. Reliability coefficient, Cronbach $alpha$ was 0.75. Using the developed instrument of ES, the ES was measured for the students of experimental group to which a inqury-based EE model was applied. The result was that the effect of ES of the students of the experimental group was not statistically significant. Futher research is needed related to the EE model based on the inquiry learning model and measurement of environmental sensitivity.