Amidino derivatives and anticoagulants and thrombosis therapeutic agents containing them

Amidino derivatives represented by the following general formula (I): ##STR1##

{where X is a group represented by R¹SO₂NR²- (wherein R¹ represents optionally substituted C_6-14 aryl, etc. and R² represents hydrogen atom, etc.), etc., Ar¹ represents 2,6-naphthylene, etc., R³ represents hydrogen atom, etc. and Y represents carboxyphenyl, etc.}

and their pharmacologically acceptable salts or solvates.