Q1-SP1-X1-MG-X2-SP2-Q2  Formula (I)

wherein Q1 and Q2 each independently represent an ethylenically unsaturated polymerizable group, SP1 and SP2 each independently represent a divalent linking group selected from the group consisting of —O—, —S—, —CO—, —NR′—(R′ represents an alkyl group having 1 to 7 carbon atoms, or a hydrogen atom), a divalent chain group and a group made by any combination of two or more thereof, X1 and X2 each independently represent a single bond, —O—, —CO—O—, —O——CO—, —CO—NH—, —NH—CO— or —O—CO—O—, and MG is represented by formula (MG-1):

-(A1-Z¹)m-A2-Z²-A3-  Formula (MG-1)

wherein A1, A2 and A3 each independently represent a 1,4-phenylene group, a heterocyclic group in which one, or two or more CH groups of a 1,4-phenylene group have been replaced by a nitrogen atom (N), a 1,4-cyclohexylene group, a heterocyclic group in which one CH₂ group, or two CH₂ groups that are not adjacent to each other of a 1,4-cyclohexylene group have been replaced by an oxygen atom (O) and/or a sulfur atom (S), a 1,4-cyclohexenylene group, or a naphthalene-2,6-diyl group, each of which may have a substituent; Z¹ and Z² each independently represent —COO—, —OCO—, —CH₂CH₂—, —OCH₂—, —CH₂O—, —CH═CH—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond; and m represents an integer of 0, 1 or 2, and

wherein R_a, R_b and R_c each independently represent -L₁-R₁, -L₂-R₂ or —NHR; at least one of R_a, R_b and R_c is —NHR; L₁ and L₂ each independently represent a single bond or a divalent linking group; R₁ and R₂ each independently represent a hydrogen atom or a substituent; and R represents a group having a polymerizable group.