A printer comprising: a pair of support members sandwiching a roll-like print medium and each provided with a swing shaft extending in a direction orthogonal to a width direction and a taking-in/out direction of the print medium; a pair of swing members each including a holding pin rotatably holding the print medium, mounted on the support members through the swing shafts so that its major surface is faced with a holding region of the print medium, capable of swing, respectively, and swinging in a direction where the pair of holding pins gets closer to each other by being brought into contact with the print medium, wherein each swing member is mounted at a position biased to a taking-out direction side of the print medium in the respective support member; a length of each swing member in a swing radial direction is smaller than a length of the respective support member in the taking-in/out direction of the print medium; and each swing member includes: a swing member body, a retreating operation portion configured to cause the respective holding pin to retreat to a direction not protruding from the swing member body by using a reaction force when the respective holding pin is brought into contact with the print medium as swing of the swing member body in contact with the print medium, and second biasing means configured to give the biasing force to the retreating operation portion to the direction where the respective holding pin protrudes from the swing member body, characterized in that the center of gravity of each swing member in the swing radial direction is disposed at a position higher than the respective swing shaft, whereby the upper part of each of the swing members swings in the direction separated from the holding region by gravity and the pair of holding pins swings in the direction separated from each other. a pair of support members sandwiching a roll-like print medium and each provided with a swing shaft extending in a direction orthogonal to a width direction and a taking-in/out direction of the print medium; a pair of swing members each including a holding pin rotatably holding the print medium, mounted on the support members through the swing shafts so that its major surface is faced with a holding region of the print medium, capable of swing, respectively, and swinging in a direction where the pair of holding pins gets closer to each other by being brought into contact with the print medium, wherein each swing member is mounted at a position biased to a taking-out direction side of the print medium in the respective support member; a length of each swing member in a swing radial direction is smaller than a length of the respective support member in the taking-in/out direction of the print medium; and each swing member includes: a swing member body, a retreating operation portion configured to cause the respective holding pin to retreat to a direction not protruding from the swing member body by using a reaction force when the respective holding pin is brought into contact with the print medium as swing of the swing member body in contact with the print medium, and second biasing means configured to give the biasing force to the retreating operation portion to the direction where the respective holding pin protrudes from the swing member body, a swing member body, a retreating operation portion configured to cause the respective holding pin to retreat to a direction not protruding from the swing member body by using a reaction force when the respective holding pin is brought into contact with the print medium as swing of the swing member body in contact with the print medium, and second biasing means configured to give the biasing force to the retreating operation portion to the direction where the respective holding pin protrudes from the swing member body, characterized in that the center of gravity of each swing member in the swing radial direction is disposed at a position higher than the respective swing shaft, whereby the upper part of each of the swing members swings in the direction separated from the holding region by gravity and the pair of holding pins swings in the direction separated from each other.