The purpose of this paper is to clarify the tasks about mathematical contents in the current curriculum. From the viewpoint of mathematical literacy, it focused specifically on the function. For attaining this purpose, firstly it is described that today's mathematical literacy include both of mathematics of application-oriented (functional) and structure-oriented (theoretical) in which it is emphasized application-oriented (functional) mathematical methods. In this regard, the function is very important to today's mathematical literacy. The function in the school mathematics is defined by a point to see a change dynamically. Therefore, the definition is application-oriented. However, the process is structure-oriented. For example, students are learning with an emphasis on the nature of primary and exponential functions such as a typical function. In addition, the end of the curricula is calculations of the differential calculus and integral calculus, and this is inconsistent with an aim of the function learning. The conclusion of this paper is that the function domain must change the curriculum from structure-oriented to application-oriented as the nature of function. For that purpose, it is necessary to emphasize the process in which it results to a function and returns a function to "real world" in unit composition and a class. The author will work on the tasks that clarified in this paper in future.