There are increasing new advances in Virtual Reality technologies as well as a rise in Immersive Virtual Environments research and in User eXperience research. Within this framework, we decided to address the overall user experience in Immersive virtual environments. Indeed, in our point of view, this topic is not fully dealt with in the scientific literature, neither in terms of user experience components nor in terms of user experience measurement methods. It is in this context that we conducted a study aiming at proposing and validating a unified questionnaire on User eXperience in Immersive Virtual Environment. Our questionnaire contains 10 scales measuring presence, engagement, immersion, flow, usability, skill, emotion, experience consequence, judgement and technology adoption. Scale construction was based on existing questionnaires. Our questionnaire was tested on 116 participants after they use the edutainment Virtual Environment “Think and Shoot”. The number of participants allows us to assess the reliability and the sensitivity of our questionnaire. Results show that 9 out of 10 subscales and 68 out of 87 items are reliable as demonstrated by an internal consistency analysis with Cronbach’s alpha and an item analysis. Findings also indicate that the scale scores from 6 subscales are considered normal distributed (e.g. presence) whereas the scale scores from 3 subscales are considered negatively skewed (e.g. skill).