This research discussed about the error in the students’ speaking performance of MEC English course. This research has two focuses, the first is to figure out the students’ speaking errors in MEC English Course, and the second is to figure out are the cause of errors on students’ errors speaking English at MEC English Course. The data were analyzed by using descriptive qualitative method. The subject of the research is 10 students of MEC English course who had taken the course for 2 months. There were two theories used in this research, they were the theory of surface strategy taxonomy on speech error by Dulay et al. (1982), the theory of the type of speech error by Clark and Clark (1977). The instrument of the research are Note-taking and audio recorder. The result of the research showed that from four types of categories of speech error which more focused on the pronunciation, from four types of categories of speech error, all categeories of errors were happened, with Addition as the most frequent error with 29 (39%) errors, followed by Omission with 24 (32%) errors, Misformation with 21 (28%) errors, and Misorder with only 1 (1%) error. The type of speech error was more focused on the performance of speaking. Out of nine types of speech errors, there were seven types that occurred they were silent pauses with 8 (28%) errors found, filled pauses with 8 (28%) errors found, repeats 4 (14%) errors found, unretraced false starts with 5 (18%) errors found, interjection 2 (6%) errors found, stutters 1 (3%) errors found, and slips of tounge with 1 (3%) errors found, where silent pauses and filled pauses happened the most. The factors of the speech error of MEC students was caused by two factors, they are cognitive factors and psychological factors.