A printer , comprising; a container configured to contain a roll (R) into which a belt-shaped print medium is wound, the roll (R) being inserted through an opening ; a guide configured to guide the roll (R), the guide being disposed in the container and having a pair of abutting faces that abut on both side faces of the roll (R); and a holding part that is movable between a first position where the holding part protrudes inwardly from the abutting face and a second position where the holding part does not protrude inwardly from the abutting face , the holding part holding the roll (R) rotatably at the first position; characterized in that the printer further comprises: a displacement part configured to be displaced with motion of the holding part ; and a biasing means configured to bias the holding part from the second position to the first position; a U-shaped groove is formed at the top of the guide ; the displacement part has an end close to the opening of the printer ; and at least the end of the displacement part is exposed through the opening of the printer such that a user can directly visually check through the opening of the printer that the displacement part is displaced so that the end of the displacement part is located in the U-shaped groove of the guide when the holding part is at the first position. a container configured to contain a roll (R) into which a belt-shaped print medium is wound, the roll (R) being inserted through an opening ; a guide configured to guide the roll (R), the guide being disposed in the container and having a pair of abutting faces that abut on both side faces of the roll (R); and a holding part that is movable between a first position where the holding part protrudes inwardly from the abutting face and a second position where the holding part does not protrude inwardly from the abutting face , the holding part holding the roll (R) rotatably at the first position; characterized in that the printer further comprises: a displacement part configured to be displaced with motion of the holding part ; and a biasing means configured to bias the holding part from the second position to the first position; a U-shaped groove is formed at the top of the guide ; the displacement part has an end close to the opening of the printer ; and at least the end of the displacement part is exposed through the opening of the printer such that a user can directly visually check through the opening of the printer that the displacement part is displaced so that the end of the displacement part is located in the U-shaped groove of the guide when the holding part is at the first position. a displacement part configured to be displaced with motion of the holding part ; and a biasing means configured to bias the holding part from the second position to the first position; a U-shaped groove is formed at the top of the guide ; the displacement part has an end close to the opening of the printer ; and at least the end of the displacement part is exposed through the opening of the printer such that a user can directly visually check through the opening of the printer that the displacement part is displaced so that the end of the displacement part is located in the U-shaped groove of the guide when the holding part is at the first position. <EOS>