The purpose of this study was to examine the contextual structure and aspects of questions in conversation that functioned as a means of thematic development. The core of conversation is what speakers talk about a particular theme through interaction, and a question plays different roles in that process. It`s found in this study that a question served as a means of thematic development, and in which contexts it performed that function was analyzed. A question developed a theme sometimes alone or sometimes along with statement or meta-speech act. When a theme was developed through a question, it was done in parallel with something else or was enriched. In the event of the parallel development of theme, several questions were often enumerated. In the event of the enrichment of theme, a speaker checked on what information the other person has while he or she developed the theme, or asked questions to attract the attention of the hearer. And the hearer used questions to make up for what the speaker had said or to ask for more information or explanation. When a theme was developed through a series of questions and answers, questions were asked based on answers about previous questions. Finally, the development of theme was interrupted when one responded by asking the same question that the other already asked or kept on asking different questions.