A transfer-section contamination prevention device includes: a powder housing section that is disposed on an upstream side relative to a transfer section in a sheet conveyance direction, and is capable of holding powder at a position near an end portion of a sheet in a sheet width direction orthogonal to the sheet conveyance direction or capable of guiding the powder to the position near the end portion of the sheet, the sheet including a base material layer, a release layer and an adhesive layer containing adhesive agent disposed between the base material layer and the release layer, the transfer section being configured to transfer a toner image to the sheet; and a powder adhesion facilitation section configured to facilitate adhesion of the powder to the lateral end portion of the sheet from the powder housing section.