A printer, comprising; a container configured to contain a roll into which a belt-shaped print medium is wound, the roll being inserted through an opening; a guide (12L, 12R) configured to guide the roll, the guide (12L, 12R) being disposed in the container and having a pair of abutting faces that abut on both side faces of the roll; 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 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 (12L, 12R); 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 (12L, 12R) when the holding part is at the first position. a container configured to contain a roll into which a belt-shaped print medium is wound, the roll being inserted through an opening; a guide (12L, 12R) configured to guide the roll, the guide (12L, 12R) being disposed in the container and having a pair of abutting faces that abut on both side faces of the roll; 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 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 (12L, 12R); 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 (12L, 12R) 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 (12L, 12R); 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 (12L, 12R) when the holding part is at the first position.