The purpose of this study is to examine the salient characteristics of the 'Question-Answer Process' (QAP) in senior high school chemistry class between pre- and in-service teachers. We first developed the 'Instrument of Question-Answer Process' (IQAP), and then, applied it to compare salient characteristics of QAP between pre- and in-service teachers. Data collection consists of classroom observation and structured-interview. Participants are seven pre-service and seven in-service chemistry teachers. The results are: (a) Both pre-and in-service teachers ask most of the questions and students ask few questions; (b) Pre-service teachers ask more lower cognitive level questions, while in-service teachers ask more higher cognitive level questions; (c) Pre-service teachers tend to ask non-volunteer students while in-service teachers tend to ask volunteer students to respond; (d) Pre-service teachers tend to be 'no feedback or ignore' after students provide answers and both pre- and in-service teachers seldom guide students to reflect on answers; and (e) The frequency of authority of 'student' in pre-service teachers' class is much higher than those in in-service teachers' class, while the frequency of authority of 'teacher and student' is much lower than those of in-service teachers' class.