There were two major purposes in this research. The first purpose was to develop the instrument of Portfolio for pre-service teachers of living technology at junior high schools and their user's manual. The second purpose was to establish the validity and reliability of the instrument. The method of this research included the literature review, nominal group, panel discussions, formal evaluation, and questionnaires. The nominal group began this study with developing the content of the instrument. The draft of the instrument was made, tested, and then revised by researchers. Then, the draft was revised by panel discussion of six experts thoroughly to establish the validity of the instrument. Five senior teachers and a professor of living technology evaluated five living technology teachers. The reliability ( Cronbach's α and Kendall Coefficient of Concordance) of the instrument was high. After that, the questionnaires were implemented to investigate the response about the usage of the instruments. Finally, the conclusion and suggestions were provided based on the result above.