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The purpose of this study was to develop the mathematics concepts scale for Matthayomsuksa 3 students under Pathumthani primary service area office 2. The four specific objectives were (1) to construct the mathematics concepts scale; (2) to validate the mathematics concepts scale; (3) to establish the norms of the mathematics concepts scale; and (4) to construct the manual of the mathematics concepts scale. Researcher used the multi-stage random sampling method to select the samples for scale validation and norms construction. Sample sizes were consisted of 592 Matthayomsuksa 3 students who studied in school under Pathumthani primary service area office 2 in second semester, academic year 2016. The developed mathematics concepts scale comprised 75 items to assess 2 mathematics concepts accordingly; 69 items for Surface Area and 6 items for Volume and Similarity. The findings were as follows: (1) The content validity of the mathematics concepts scale, investigated by calculating the Item-objective Congruence index (IOC), were in the range of 0.60-1.00 (2) The item difficulty index were in the range of 0.34-0.79 (3) The item discrimination index were in the range of 0.2-0.77 (4) The reliability for Surface Area and Volume concept, and Similarity concept were 0.92 and 0.73, respectively (5) The local norms for the mathematics concepts scale interpretation presented in the form of normalized T-score in the range of T3-T91 and (6) The manual of the mathematics concepts scale was suitable and fully important composition, easy to understand and convenient for usability.