Disclosed is a block copolymer characterized by containing a block (A) containing one or more repeating units represented by the general formula (I) below, one or more repeating units represented by the general formula (II) below and one or more repeating units represented by the general formula (III) below, and a block (B) containing one or more repeating units represented by the general formula (III) below and one or more repeating units represented by the general formula (IV) below. (I) (In the formula (I), R1, R2, R3 and R4 may be the same or different and respectively represent a hydrogen atom or an alkyl group; R5, R6, R7 and R8 may be the same or different and respectively represent an alkyl group, an alkoxy group or the like; and a, b, c and d may be the same or different and respectively represent an integer of 0-3. When a plurality of R5's, R6's, R7's and R8's are present, they may be the same as or different from one another.) —Ar1— (II) (In the formula (II), Ar1 represents a divalent heterocyclic group containing a five-membered ring.) —Ar2— (III) (In the formula (III), Ar2 represents an arylene group.) —Ar3— (IV) (In the formula (IV), Ar3 represents a divalent aromatic amine.)