In this paper I turn to different conceptions of interest. There are several theories in the field of political philosophy about what interest is and therefore several conceptions of interest exist. Three pairs of interest are clarified: interest as welfare and interest as resource, reflective interest and volitional interest, public interest and private interest. Especially, interests in compulsory licenses are also described, which are including compulsory licenses and the conceptions of interest, diversity of interests and interest in pharmaceutical industry. By these analyses, we can see interests in compulsory licenses in general and in pharmaceutical industry.