This paper studied the case types of the causative arguments of the Austronesian languages in Taiwan. The languages of the Austronesian family in Taiwan have a unique focus structure that is largely divided into agent focus and non-agent focus(patient focus, locative focus, instrumental focus, peripheral focus). This unique focus structure affects the argument case structure of the causative sentences. This paper investigates the case structure of the two argument causative sentences, three argument causative sentences, and four argument causative sentences of the Austronesian languages in Taiwan, respectively, and classifies the types. It can be seen that the case structure types of the argument differs according to the focus structure types in all of the two argument causative sentences, three argument causative sentences, and four argument causative sentences. In the case of the agent focus two argument causative sentences of the Austronesian languages in Taiwan, the types of argument case can be classified into 4 types. And in all languages, there was a common characteristic that the causer appears as the nominative case. The case structure in which the causer appears as the nominative and the causee appears as the ablative was the most with 8 languages. In the case of the non-agent focus two argument causative sentences of the Austronesian languages in Taiwan, the types of argument case can be classified into 4 types. In the non-agent focus two argument causative sentences, the patient focus sentence and the locative focus sentence were found as the non-agent focus sentence. Languages with non-agent focus, and with the case structure in which the causer appears as the genitive and the causee appears as the nominative were the most with 11 languages. In the case of the agent focus three argument causative sentences of the Austronesian languages in Taiwan, the types of argument case can be classified into 4 types. And in all languages, there was a common characteristic that the causer appears as the nominative case. In the case of the non-agent focus three argument causative sentences of the Austronesian languages in Taiwan, the types of argument case can be classified into 14 types. there was a common characteristic that almost all of the causer appears as the genitive case. Four types of non-agent focus sentence were discovered in the non-agent focus three argument causative sentences, patient focus sentence, locative focus sentence, instrumental focus sentence, and peripheral focus sentence. Languages with non-agent focus, and with the case structure in which the causer appears as the genitive and the causee appears as the nominative and object appears as the ablative were the most with 5 languages. It is difficult to systematically classify the case structure of four argument causative sentences of the Austronesian languages in Taiwan because examples of four argument causative sentences were found only in Puyuma, Sakijaya, and Saroan references. However, considering only the examples found, there was a commonality in that the causer appeared as the genitive case in all three languages. After examining and classifying case types of causative arguments of Austronesian languages in Taiwan, this study compares them with the case types of causative arguments suggested by Dixon (2000:30-83). As a result, it was found that the case types of causative arguments of Austronesian languages in Taiwan and the case types of causative arguments suggested by Dixon only partially matched each other and most of them did not match.