According to one embodiment, there is provided a printer including a print head, a platen roller, a sheet position sensor, an antenna, and a movable portion. The print head is configured to print on a strip-shaped sheet. The platen roller is configured to move the sheet pinched between the platen roller and the print head along a longitudinal direction of the sheet. The sheet position sensor is provided on a substrate disposed on an upstream side of the print head in a conveyance direction of the sheet, and is configured to detect a position of the sheet. The antenna is provided on the substrate and is configured to write information to a wireless tag provided on the sheet. The movable portion is configured to move the substrate along a width direction of the sheet.