本文針對近年來快速發展的台灣上櫃審計市場，進行審計公費決定因素之實證研究，以評估台灣上櫃審計市場之運作。基於台灣資本市場並未強制要求公司揭露審計公費資訊，本文採用問卷調查的方式，收集台灣上櫃公司民國88年度之審計公費資訊，有效樣本共計75家公司。本文之實證結果發現，就上櫃公司而言，最重要的審計公費決定因素乃事務所提供之審計服務項目，特別是財務預測核閱及其他審計服務，而非以上市公司為研究對象所常見之客戶規模變數。本文推論因上櫃公司規模明顯較上市公司小、申請上市典上櫃公司之基本特性不同、對審計服務類型之需求不同、以及會計師於提供二群公司審計服務時之投入不同，乃為本文實證結果與過去各國針對上市公司審計公費決定因素研究結果不同之可能原因。基於本文之研究結果，我們認為未來於探討審計公費決定因素相關議題時，宜將上市與上櫃公司分別探討，以提高實證結果之效度；且探討公司審計公費決定因素時，宜考慮樣本公司之規模。

The purpose of this study is to investigate the determinants of audit fees of the Taiwanese OTC companies. Due to the lacking of mandatory disclosure requirement of audit fees in Taiwan's capital market, questionnaires are distributed to Taiwanese OTC companies to collect data about audit fees in year 1999. Data from 75 companies is valid and used in this study. The empirical results of this study indicates that, the number of the categories of assurance service provided by the auditor, rather the size of the auditee, which is the prevalent and most important determinate of audit fees in most capital markets, is the major determinant of the audit fees for the Taiwanese OTC companies. The study infers that the unique fees determinants of the OTC companies are due to the distinctive company scales and operating characteristics, as well as the service categories required by the auditees. In order to increase the research validity of research on fees determinant issue, the study also suggestes that it is necessary to conduct separate investigations on the determinants of audit fees for listed companies and OTC companies and to take size effect of the auditee into consideration.