This article is a report about the development of a new instrument to measure South Korean elementary teachers’ anxiety about teaching mathematics; it explores the instrument’s underlying dimensions by examining the responses of 64 South Korean elementary teachers. From the conceptual framework, I designed three sub-scales in the Survey Items of the South Korean Elementary Teachers’ Anxiety about Teaching Mathematics (S-ATM): preference for mathematics or mathematics instruction, confidence in mathematics or mathematics instruction, and effectiveness of mathematics instruction. I conducted analyses of the principal components to determine the factor structures of the scales. The results showed that the relativity for each sub-scale’s Cronbach’s alpha was greater than .700. I also examined this scale’s validity by surveying the same participants with the Mathematics Teaching Efficacy Belief Instrument and comparing the results. The results demonstrated that the mathematics teaching anxiety sub-scales were significantly collated with the validation scale statistically. Its psychometric properties were sound, and the S-ATM instrument can be recommended for use in investigating South Korean elementary teachers’ anxiety about teaching mathematics