Disclosed are an organic thin-film transistor and a manufacturing method thereof, the organic thin-film transistor comprising a support and provided thereon, a gate electrode, an insulation layer, a source electrode, a drain electrode, and an organic semiconductor layer, the support comprising at least one of resins, and the organic semiconductor layer containing at least one of organic semiconducting materials, wherein a phase transition temperature of one of the organic semiconducting materials is not more than a glass transition point of one of the resins.