A printer, comprising: a printing component configured to print on a strip-shaped sheet; sheet; a housing configured to house the strip-shaped sheet and the printing component, and comprising a sheet ejection port for ejecting upward the strip-shaped sheet that has passed through the printing component; a cutting component arranged between the printing component and the sheet ejection port and configured to cut the strip-shaped sheet by either a first method of cutting the strip-shaped sheet in an entire width direction or a second method of cutting the strip-shaped sheet and leaving uncut a central portion of the strip-shaped sheet in the width direction; first protrusions protruding from an inner periphery of the sheet ejection port, and provided at a plurality of locations along the width direction of the strip-shaped sheet to face a first surface of the strip-shaped sheet which is a surface to be printed; and second protrusions protruding from the inner periphery of the sheet ejection port, provided at a plurality of locations along the width direction of the strip-shaped sheet at positions deviated from the first protrusions in the sheet width direction to face a second surface which is a back surface of the first surface of the strip-shaped sheet, and configured to bend the strip-shaped sheet in an undulating shape in the width direction between the first protrusions and the second protrusions, wherein a protrusion height of at least either the first protrusions or the second protrusions in a predetermined region of the central portion in the width direction of the strip-shaped sheet is lower than protrusion heights of the first protrusions and the second protrusions in other regions. a printing component configured to print on a strip-shaped sheet; sheet; a housing configured to house the strip-shaped sheet and the printing component, and comprising a sheet ejection port for ejecting upward the strip-shaped sheet that has passed through the printing component; a cutting component arranged between the printing component and the sheet ejection port and configured to cut the strip-shaped sheet by either a first method of cutting the strip-shaped sheet in an entire width direction or a second method of cutting the strip-shaped sheet and leaving uncut a central portion of the strip-shaped sheet in the width direction; first protrusions protruding from an inner periphery of the sheet ejection port, and provided at a plurality of locations along the width direction of the strip-shaped sheet to face a first surface of the strip-shaped sheet which is a surface to be printed; and second protrusions protruding from the inner periphery of the sheet ejection port, provided at a plurality of locations along the width direction of the strip-shaped sheet at positions deviated from the first protrusions in the sheet width direction to face a second surface which is a back surface of the first surface of the strip-shaped sheet, and configured to bend the strip-shaped sheet in an undulating shape in the width direction between the first protrusions and the second protrusions, wherein a protrusion height of at least either the first protrusions or the second protrusions in a predetermined region of the central portion in the width direction of the strip-shaped sheet is lower than protrusion heights of the first protrusions and the second protrusions in other regions.