[Problem] To provide a compound which is useful as an agent for preventing and/or treating kidney diseases. [Means for Solution] The present inventors have studied compounds having a trypsin inhibitory activity, and have confirmed that a guanidinobenzoic acid ester compound has a trypsin inhibitory activity, thereby completing the present invention. The guanidinobenzoic acid ester compound of the present invention can be used as an agent for preventing and/or treating kidney diseases (for example, chronic kidney disease, acute glomerulonephritis, acute kidney injury, and the like) as an agent which will substitute low-protein diet therapy, and/or as an agent for preventing and/or treating trypsin-related diseases (for example, chronic pancreatitis, gastroesophageal reflux disease, hepatic encephalopathy, influenza, and the like).Bu buluş bir farmasötik bileşimin, örneğin böbrek hastalıklarının tedavisine yönelik bir farmasötik bileşimin bir etken bileşeni olarak yararlı olan bir guanidinobenzoik asit ester bileşiğine ilişkindir.