A method of manufacturing an organic thin film transistor comprising, on a substrate: 1) a gate electrode; 2) an organic semiconductor layer containing an organic semiconductor compound which has a molecular weight of ≥ 2, 000 and has a repeating unit of the formula -(D-A)-, wherein A is an electron acceptor unit including a partial structure having at least one of a sp2 nitrogen atom, a carbonyl group, or a thiocarbonyl group in a ring structure, and D is an electron donor unit including a divalent aromatic heterocyclic group having at least one of a N atom, an O atom, a S atom, or a Se atom in a ring structure or a divalent aromatic hydrocarbon group consisting of a fused ring structure having two or more rings, as a partial structure, 3) a gate insulating layer provided between the gate electrode and the organic semiconductor layer; and 4) a source electrode and a drain electrode which are provided to be in contact with the organic semiconductor layer and are linked to each other via the organic semiconductor layer, wherein the organic semiconductor layer is in contact with a layer containing a resin or further contains the resin, the resin has at least one repeating unit of any of formulae (C-Ia) to (C-Id): wherein R 10, R 11 each are H, F or alkyl, W 3 is an organic group having one or more selected from F, a Si-containing group, C ≥2 -alkyl, cycloalkyl, aryl and aralkyl, W 4 is an organic group having one or more selected from F, a F-containing group, a Si-containing group, alkyl and cycloalkyl, W 5, W 6 each are an organic group having one or more selected from a F-containing group, a Si-containing group, alkyl, cycloalkyl, aryl and aralkyl, Ar 11 is a (r+1)-valent aromatic ring group, r is an integer of 1-10, and s is 0 or 1; characterised in that the method comprises a step of applying a mixed solution containing the organic semiconductor compound and the resin. 1) a gate electrode; 2) an organic semiconductor layer containing an organic semiconductor compound which has a molecular weight of ≥ 2, 000 and has a repeating unit of the formula -(D-A)-, wherein A is an electron acceptor unit including a partial structure having at least one of a sp2 nitrogen atom, a carbonyl group, or a thiocarbonyl group in a ring structure, and D is an electron donor unit including a divalent aromatic heterocyclic group having at least one of a N atom, an O atom, a S atom, or a Se atom in a ring structure or a divalent aromatic hydrocarbon group consisting of a fused ring structure having two or more rings, as a partial structure, semiconductor compound which has a molecular weight of ≥ 2, 000 and has a repeating unit of the formula -(D-A)-, wherein A is an electron acceptor unit including a partial structure having at least one of a sp2 nitrogen atom, a carbonyl group, or a thiocarbonyl group in a ring structure, and D is an electron donor unit including a divalent aromatic heterocyclic group having at least one of a N atom, an O atom, a S atom, or a Se atom in a ring structure or a divalent aromatic hydrocarbon group consisting of a fused ring structure having two or more rings, as a partial structure, 3) a gate insulating layer provided between the gate electrode and the organic semiconductor layer; and 4) a source electrode and a drain electrode which are provided to be in contact with the organic semiconductor layer and are linked to each other via the organic semiconductor layer, wherein the organic semiconductor layer is in contact with a layer containing a resin or further contains the resin, the resin has at least one repeating unit of any of formulae (C-Ia) to (C-Id): wherein R 10, R 11 each are H, F or alkyl, W 3 is an organic group having one or more selected from F, a Si-containing group, C ≥2 -alkyl, cycloalkyl, aryl and aralkyl, W 4 is an organic group having one or more selected from F, a F-containing group, a Si-containing group, alkyl and cycloalkyl, W 5, W 6 each are an organic group having one or more selected from a F-containing group, a Si-containing group, alkyl, cycloalkyl, aryl and aralkyl, Ar 11 is a (r+1)-valent aromatic ring group, r is an integer of 1-10, and s is 0 or 1; characterised in that the method comprises a step of applying a mixed solution containing the organic semiconductor compound and the resin. R 10, R 11 each are H, F or alkyl, W 3 is an organic group having one or more selected from F, a Si-containing group, C ≥2 -alkyl, cycloalkyl, aryl and aralkyl, W 4 is an organic group having one or more selected from F, a F-containing group, a Si-containing group, alkyl and cycloalkyl, W 5, W 6 each are an organic group having one or more selected from a F-containing group, a Si-containing group, alkyl, cycloalkyl, aryl and aralkyl, Ar 11 is a (r+1)-valent aromatic ring group, r is an integer of 1-10, and s is 0 or 1;