This study investigated the interactions between starch and starch - derived materials and fluorescent materials. Many researchers have used fluorescent materials to monitor the internal structure of starch, which is an effective method. The purpose of this study was to observe the internal structure of starch by using fluorescent material and to check how much fluorescent material could be loaded inside the starch. For this, a standard curve of the fluorescent material was obtained and a linear graph corresponding to the concentration was obtained. Next, the incorporation of the fluorescent material into the starch was confirmed by CLSM in the infusion experiment. Infusion experiments were carried out to quantify the amount of fluorescent substance in starch, but the error was confirmed in this experiment. The error was caused by the action of starch and the fluorescent substances FD4 and NaFl, resulting in an increase or decrease in fluorescence intensity. To find the cause, dextrin, amylose and amylopectin, which are starch-derived substances, and α, β, γ-cyclodextrin, which can form inclusion compounds, were used. The fluorescent materials were merbromin, NaFl, and FITC. As a result, the fluorescence intensity of the fluorescent material was significantly influenced by the concentration of amylose and amylopectin. This result implies that there may be errors in the analysis of the phenomenon or observation of the starch using the fluorescent substance. We still do not know exactly the cause of this phenomenon, so further research is needed.