本文旨在探討非審計服務與事務所規模對盈餘價值攸關性（以盈餘反應數衡量）之影響，本文以2003年至2006年上市及上櫃公司共計2,958個觀測值為樣本。實證結果發現，非審計服務與盈餘價值攸關性呈顯著正相關，顯示公司向會計師購買非審計服務，會減少投資人評估盈餘的資訊風險，進而增加盈餘價值攸關性。另外，本文發現由四大會計師事務所查核的公司，其盈餘價值攸關性顯著優於非四大會計師事務所查核的公司，顯示大型會計師事務所有較強的誘因提供高品質的審計，降低報導盈餘的資訊風險，進而增加盈餘價值攸關性。然而，客戶向大型會計師事務所購買非審計服務，並無法進一步增加盈餘價值攸關性。

This paper examines the impact of non-audit services and auditor size on the value relevance of earnings (measure with earnings response coefficient). Our samples include 2,958 observations of TSE (Taiwan Stock Exchange) and OTC (Over-the-counter) firms from 2003 to 2006. We find a significantly positive relationship between non-audit services and the value relevance of earnings, which suggests that the provision of non-audit services by auditor reduces investor's perception of the information risk associated with the reported earning, in turn, increases the value relevance of earnings. In addition, we find that the value relevance of earnings of Big four clients is significantly higher than for non-Big four clients. The results indicate that the big auditors have stronger incentives to provide higher quality audit, then they can mitigate the information risk associated with the reported earning, in turn, increases the value relevance of earnings. However, the provision of non-audit services by Big four auditor is unable to further increase the value relevance of earnings.