The present invention relates to a biaryl derivative or a pharmacologically acceptable salt thereof having an excellent collagen-synthesis inhibition activity. A biaryl derivative having a structure represented by the following General Formula (I) or a pharmacologically acceptable salt thereof: wherein R1 represents a C6-C10 aryl group which is substituted with one to three group(s) each independently selected from the group consisting of a group defined by formula R-L-, a di-(C1-C6 alkyl)amino group, a di-(C1-C6 alkyl)aminosulfonyl group, a hydroxyaminocarbonyl group, and a halogen atom, and so on; R represents a C1-C6 alkyl group, and so on; L represents a sulfonyl group, an aminosulfonyl group, or a sulfonylamino group, and so on; R2 represents a hydrogen atom, and so on; A represents a group defined by formula (II), (III), or (IV); R3 represents a C1-C6 alkyl group, and so on; and R4 represents a C1-C6 alkyl group, and so on.