A printing apparatus, comprising: a holding unit configured to hold a roll sheet with a continuous sheet wound in a roll form; a printing unit configured to perform printing on the sheet supplied from the roll held by the holding unit; a lower guide that is disposed on a lower side of the roll sheet so as to move in accordance with a change in an outer diameter of the roll sheet and guides a lower surface of the sheet fed from the roll sheet; a lower side contact body (7, 8) that contacts with an outer circumferential surface of the roll sheet at a first contact position and is supported by the lower guide; an upper guide that is disposed above the lower guide (4,7) so as to move in accordance with the change in the outer diameter of the roll sheet and to face an upper surface of the sheet fed from the roll sheet, the upper guide including an upper side contact body that contacts with an outer circumferential surface of the roll sheet at a second contact position; a driving unit configured to rotate the roll sheet held by the holding unit in a forward direction and supply the sheet to the printing unit so as to pass between the upper guide and the lower guide (4,7) and to rotate the roll sheet held in the holding unit in a backward direction opposite to the forward direction so as to allow the leading end portion of the sheet to be separated from the outer circumferential surface when passing through the second contact position; a sensor configured to change an output in accordance with a distance to the sheet of the roll sheet held by the holding unit; and a control unit configured to control rotation of the roll sheet by the driving unit in the forward direction and in the backward direction, and to switch a rotation direction of the driving unit from the backward direction to the forward direction on the basis of the output of the sensor during the rotation of the roll sheet in the backward direction, wherein the sensor is disposed at a position which the sheet separated from the outer circumferential surface of the roll sheet approaches in a case where the leading end portion of the roll sheet rotating in the backward direction passes through the second contact position, and wherein, in a circumferential direction of the roll sheet, a distance (α) between a detection position of the sensor and the first contact position is smaller than a distance (β) between the second contact position and the first contact position. a holding unit configured to hold a roll sheet with a continuous sheet wound in a roll form; a printing unit configured to perform printing on the sheet supplied from the roll held by the holding unit; a lower guide that is disposed on a lower side of the roll sheet so as to move in accordance with a change in an outer diameter of the roll sheet and guides a lower surface of the sheet fed from the roll sheet; a lower side contact body (7, 8) that contacts with an outer circumferential surface of the roll sheet at a first contact position and is supported by the lower guide; an upper guide that is disposed above the lower guide (4,7) so as to move in accordance with the change in the outer diameter of the roll sheet and to face an upper surface of the sheet fed from the roll sheet, the upper guide including an upper side contact body that contacts with an outer circumferential surface of the roll sheet at a second contact position; a driving unit configured to rotate the roll sheet held by the holding unit in a forward direction and supply the sheet to the printing unit so as to pass between the upper guide and the lower guide (4,7) and to rotate the roll sheet held in the holding unit in a backward direction opposite to the forward direction so as to allow the leading end portion of the sheet to be separated from the outer circumferential surface when passing through the second contact position; a sensor configured to change an output in accordance with a distance to the sheet of the roll sheet held by the holding unit; and a control unit configured to control rotation of the roll sheet by the driving unit in the forward direction and in the backward direction, and to switch a rotation direction of the driving unit from the backward direction to the forward direction on the basis of the output of the sensor during the rotation of the roll sheet in the backward direction, wherein the sensor is disposed at a position which the sheet separated from the outer circumferential surface of the roll sheet approaches in a case where the leading end portion of the roll sheet rotating in the backward direction passes through the second contact position, and wherein, in a circumferential direction of the roll sheet, a distance (α) between a detection position of the sensor and the first contact position is smaller than a distance (β) between the second contact position and the first contact position.