The purpose of this study was to identify the preferable motivation types in science-learning and to find out the relationship between these types and scientific achievement of students in the secondary school. The subjects of the study were the second grade 581 students sampled by random cluster sampling method in three middle schools and three high schools. Three motivation types in science learning were analyzed, and they were named to task-orientation, ego-orientation and work-avoidance. From our results, secondary school students preferred task-orientation and work-avoidance to ego-orientation. In the case of task-orientation, high school students, especially in male group, had much preferable tendency than that of middle school students (p<0.001). It is interpreted that, as the level of scientific content of texts or the cognitive level of students were higher, a preference for the motivation type was focused to the task-orientation, especially in male group. In the case of ego-orientation, the female group showed much preferable tendency than that of male group in middle school (p<0.05). However, the female group in high school students was not different from the other groups in this motivation type. In the case of work-avoidance, there were not only a significant difference between males and females in the middle school (p<0.001), but also difference between middle and high school students in female group (p<0.05). It showed that female group had much preferable tendency than that of male group, and this tendency was decreased to the higher grade students in secondary school. From the analysis of correlation between motivation types and scientific achievement, task-orientation and work-avoidance were correlated to the scientific achievement. Its results were interpreted that the scientific achievement could be accomplished by the external motivation stimulus as well as the scientific content of texts. The task-orientation were comparatively correlated to the intelligence quality. It means that the students having high intelligence quality showed much preferable for the task-orientation.