This research's aim is to figure out the impact of company size, audit complexity, audit risk, and company risk on audit fee in companies of trading, service and investment that listed on the Indonesia Stock Exchange in 2017-2021. The variables in this research are Company Size, Audit Complexity, Audit Risk, and Company Risk as Independent Variables while Audit Fee as Dependent Variable. The population that used are companies of trading, service, and investment that registered on the Indonesia Stock Exchange in 2017-2021. Purposive sampling method used to determine the sample of this research and the sample is 16 companies for five years of research. Multiple regression analysis as the analytical method in testing the independent variables that affecting the dependent variable. The results of the research indicate variables that have effect on audit fee are company size and company while audit complexity and audit risk have a negative effect on audit fee.