Objective: We aimed to understand the frustrations of surrogate decision makers, such as family members of patients who were informed that they were in their end-of-life phase, by analyzing the content of their interviews. Methods: The participants were surrogate decision makers, such as family members of patients who died at Hospital A after being informed that they were in their end-of-life phase. A request for cooperation in the study was sent via mail to 112 individuals, of whom 11 responded to the request. After receiving an explanation, they consented to the study and were subsequently interviewed. The interviews consisted of questions concerning their frustrations as surrogate decision makers. In the analysis, the situations associated with the frustrations of surrogate decision makers were extracted and classified into categories and subcategories according to the abstraction levels determined based on the similarity of semantic contents. The patients’ decision-making was revealed from five of those interviewed, and six individuals were analyzed. Results: There were 12 representative semantic contents that were organized into the following 5 subcategories (<< > >) and 2 categories ([]): <<I have conflicting feelings regarding whether I am the right person to decide the patient’s life when his/her will is unclear>> and <<I feel troubled whether I have the right to decide when I have avoided listening to the patient’s true feelings > >, which constituted [troubles concerning the right to decide], and <<I feel regretful regardless of the choice I make > >, <<I feel influenced even after reaching a decision > >, and <<I feel anxious every time the patient’s condition changes > >, which constituted [continued frustrations regardless of their choices]. Conclusion: Surrogate decision makers were facing a dilemma concerning their right to decide as well as continued frustrations regardless of their choices. We believe that it is essential to understand the difficult situation of the surrogate decision makers and appropriately support them.