The main purpose of this study is to examine (1) whether there is any noticeable difference in the vocabulary level of example sentences for English grammar instruction between textbooks based on the former course of study (CS) and those based on the present CS, and (2) whether there is any change in the results if the sentences are divided between those extracted from the main-lesson passages and those not. Various researches have been made on the vocabulary level of reading passages, but there have been few studies in terms of example sentences for English grammar instruction. In addition, it is expected that whether the sentences are extracted from the passages or not can affect the vocabulary level of the overall example sentences. Therefore, example sentences are collected from 48 textbooks based on the present and the former CS. Words in the sentences are classified into different vocabulary levels based on the latest version of JACET 8000. Residual analysis, χ2-test and Cramer V were mainly used as data analysis. The results implied (1) that the vocabulary level in the example sentences based on the present CS tends to be higher than those based on the former one, and (2) that the sentences not extracted from the reading passages affect the rise of the vocabulary level.