Debt is one of the important sources of fund for Indonesian companies. The previous research of manufacturing companies listed on Indonesia Stock Exchange (IDX) in 2015-2017 indicated debt to equity ratio is 111%. The debt could probably cause disadvantages. There are requirements from external parties when companies request sources of funds, especially when conducting Initial Public Offerings (IPOs). There should also be debt covenants between company and debtor. However, the proper debt management will have a positive effect on capital structure. Therefore, this research aims to explore the effect of long-term debt (LTD), fixed assets (FA), earnings per share (EPS) and net income (NI) on capital structure (CS), assuming that LTD will moderate the effect of FA, EPS, and NI on equity. The research sample is 32 of manufacturing companies that conducted IPOs on IDX in period of 2018-2020, which were purposively taken based on the criteria of publishing annual financial report and having complete data needed in this research. Fortunately, the research found 11 companies for 2018; 9 companies for 2019; and 12 companies for 2020. The multiple linear regressions with cross data section show NI, FA, and EPS affect CS significantly; while LTD does not influence CS. However, the LTD significantly quasi-moderates the effect of FA on CS. While the LTD significantly moderates purely the effect of NI on CS. Therefore, the companies should manage the NI for investment in FA and increase the effectiveness of LTD's management in optimizing capital structure.