Abstract:The purpose of this research is to determine the frequency of the causes of difficulties in the introductory quantum physics of high school and university students in science education departments. For this purpose, qualitative data of student opinions collected in another study was used to develop a Likert scale. The scale has a five-factor structure according to the result of exploratory factor analysis. The data were analyzed and interpreted taking into consideration factors. As a sample, 702 people were selected, including 411 students of Science Education Department at five different universities and 291 high school students in five different high schools. According to the results, the difficulty levels of most of the items are medium. Students have positive opinions using animation, simulation, and experiments in courses. There is no general problem in the regular attendance of the students to the course and to attach importance to the subjects. The idea of "there are no everyday life examples about the subjects of quantum" is one of the most common difficulties. Females are more interested in quantum physics than males. In addition, the university students are more positive than the high school students about different teaching methods.