The aim of this study is to clarify the semantic and pragmatic functions of indeed as a discourse marker. Although it has been highly placed among the whole discourse markers, indeed has not received much attention and its functions have not been clearly provided. Accordingly, the study examines how to classify the discourse markers in the previous studies and explores the meanings of indeed as a modal adverb and functions as a discourse marker. Presupposing that the meanings of indeed as an adverb and a discourse marker are not irrelevant, this study presents three functions of indeed in a discourse, such as intensifying, confirming, and adding extra information. This study has the following significances. The study has comprehensively analyzed the functions of indeed by using BNC web data and clarify functions of indeed.