The audit process plays an essential role in financial reporting because it increases the reliability, credibility and overall quality of accounting information. Therefore, financial reporting is of primary importance for assessing creditors' ability to repay a company's debts. Thus, high-quality auditing reduces skepticism, gains the trust of capital providers in financial statements, and affects companies' access to finance. In addition, non-audit costs due to the effects of knowledge overflow indicate higher accounting quality and high quality of a company's accounting system. Therefore, the purpose of this study is to investigate whether normal and abnormal audit costs affect financial constraints. The statistical population of companies listed on the Tehran Stock Exchange between 1390 and 1390 and using the information of 118 companies and multivariate linear regression method was tested to hypothesis that the test results showed that the variable of normal and abnormal audit costs have a significant relationship with financial constraints. . In other words, normal and abnormal audit costs have a significant effect on financial constraints.