Disclosed is a therapeutic agent for treating and / or improving retinal diseases such as age-related macular degeneration. A therapeutic agent for retinal diseases such as age-related macular degeneration, which comprises a sodium / glucose cotransporter 2 (SGLT2) inhibitor as an active ingredient. [Selection] Figure 4【課題】加齢黄斑変性症等の網膜疾患を治療及び/又は改善する治療剤を提供すること。【解決手段】ナトリウム/グルコース共輸送体2(SGLT2)阻害物質を有効成分とする加齢黄斑変性症等の網膜疾患の治療剤である。【選択図】図4