Disclosed is a 2-aminoquinazoline derivative represented by formula (I) [wherein R1 represents a hydrogen atom or the like; R2 represents a hydrogen atom; R3 represents a group represented by formula (II) (wherein A1 represents a group represented by formula (III) or the like; R8 represents a lower alkyl or the like; and R9 represents an aryl which may have a substituent, or the like); R4 represents a hydroxy or the like; and R5 represents an aryl which may have a substituent, or the like] or a pharmaceutically acceptable salt thereof.
