[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).