With the change of medical environment, people are taking interest not just in treatment but in the prevention of oral diseases. As people's interest in oral diseases increases, the number of dental institutions is increasing continuously and this is heightening the necessity and importance of professional dental hygienists equipped with expert knowledge of oral health. Thus the present study purposed to survey and analyze the current state and weight of works carried out by dental hygienists, and to propose dental hygienists' works desirable in the medical environment changing its focus from treatment to prevention. The results of this study are as follows; 1. In the results of dividing dental hygienists' works into oral examination and preliminary examination, preventive works, assistance to dental treatment, oral health education, hospital administration and management, and surveying the performance rate of these works, the work of the highest performance rate in preliminary examination was collection of patients' systemic history (87.6%). It was also scaling (96.9%) in preventive dental treatment, preparation for treatment (96.5%) in assistance to dental treatment, education on the toothbrushing method (92.3%) in oral health education, and tool disinfection and management (72.2%) in hospital administration and management. 2. When the performance rate was surveyed according to age, institution, and work experience, the performance rate by work area was highest in dental hygienists aged between 27~28, those working at a dental clinic, and those with 4~6 years' work experience. 3. The weight of dental hygienists' works was high in order of assistance to dental treatment (59.1%), observation of oral health condition and preliminary examination (12.4%), oral health education (12.4%), hospital administration and management (10.4%), and preventive dental treatment (5.8%), but in the results of surveying perception on the importance of works, the importance was high in order of oral health education (34.7%), preventive dental treatment (29.0%), observation of oral health condition and preliminary examination (19.3%), assistance to dental treatment (11.2%), and hospital administration and management (5.8%), showing that the weight of works carried out current was different from perception on the weight of works regarded as important. 4. To the question on parts to be developed in response to the change of medical environment, the most frequent answers were the establishment of their roles as preventive dental practitioners (75.7%), and the establishment of their roles as oral health educators (74.9%). This was consistent with the works that dental hygienists gave the highest weight to, and suggested that dental hygienists regarded preventive dental treatment as most important. Development of abilities to give counsel to patients was 55.2%, acquisition of theoretical knowledge of dental treatment 42.1%, improvement in quality as a hospital manager 28.2%, and acquisition of skills to assist dental treatment 23.2%. These show that, even with regard to the development of future oriented dental hygienists' capacities, assistance to dental treatment was perceived less important as it was with regard to the importance of work.