The purpose of this study was to identify the factors affecting depression according to the causes of suicidal ideation. The data used the 2021 Community Health Survey data. The participants of the study were 5,328 adults between the ages of 20 and 60 who responded that they had suicidal thoughts in the past year. For the analysis of the data, a composite sample analysis was performed using the SPSS 25.0 program. The results of the study are as follows. 1) In the economic difficulties group, age, gender, education level, economic activity, job change due to COVID-19, life satisfaction, subjective health status, stress, sleep time, and annual unmet medical care were the main factors related to depression. 2) In the interpersonal problem group, age, gender, education level, economic activity, life satisfaction, subjective health status, smoking, drinking, stress, and sleeping time were the main factors associated with depression. 3) In the disease and disability group, age, marital status, education level, life satisfaction, smoking, stress, sleep time, and annual unmet medical care were the main influencing factors of depression. Therefore, in order to reduce the rate of suicide and prevent depression, it is necessary to establish various strategies according to the causes of suicidal ideation and the influencing factors of depression.