Despite the considerable change in alcohol consumption during the COVID-19 pandemic, the impact of the pandemic on the suicide rate in terms of alcohol consumption was not studied. This study was performed to examine whether the change in the suicide rate during the COVID-19 pandemic was related to alcohol consumption and whether the relation was specific to suicides when compared to mortality due to other causes. We performed a comparative interrupted time series (CITS) analysis for the suicide rate of people aged 19 to 60 with three comparison groups (the suicide rate of people aged 19 and under, the cancer death rate of people aged 19 to 60, and alcohol-induced death rates). The suicide rate of people aged 19 to 60 and alcohol consumption per capita, along with alcohol-induced death rates, continued to decrease during the pandemic in 2020 and 2021, while the suicide rate of people aged 19 and under and the cancer death rate showed increases. In the comparative interrupted time series model, alcohol consumption had an increasing effect on the adult suicide rate compared to comparison groups when time trends and changes associated with COVID-19 were adjusted. This study shows that the decrease in the adult suicide rate in Korea during the pandemic was associated with the decrease in alcohol use among the adult population. Considering that means restriction is the most effective way of controlling suicide and that alcohol can be the most potent and final trigger for suicide, the decrease in suicides during the pandemic and its association with alcohol consumption should be understood as a call for further efforts to decrease alcohol consumption.