Abstract:
Education have an important role in character building of students. The characters that can be developed in learning mathematics are honest, disciplined, diligent, responsibility, and self- confidence. The characters can be done through a process of habituation, integrated in subject and the teacher as a model for students. Achievement of the character in learning Mathematics is often difficult to detect because the teacher does not have an instrument that can measure the character achieved by student. Therefore, an instrument to measure the characters building in mathematics instructional will be useful for teachers to see an indication of the character of student achievement. The purpose of this study was to develop an instrument to measure the character building of students in mathematics instructional. This study was carried out from the development of the conceptual definition, operational definitions, determination constructs, dimensions, and indicators, preparation of the blue-print and item, expert validation, field testing, and data analysis. Data trial results were analysed using factor analysis and structural equation modelling analysis. The results showed that there are five main factors constructed the instrument character with good validity and reliability.