Printing apparatus and roll holding device

A printing apparatus that performs printing on a sheet drawn out from a roll in which the sheet is rolled up around a core pipe, comprising:

• a roll holding unit including a flange and configured to hold the roll;
• a core portion extending from one side of the flange along a rotation axis of the roll and configured to be inserted into a hollow portion of the core pipe from an end portion of the core pipe;
• a shaft portion extending from the other side of the flange along the rotation axis;
• a flange bearing including a bearing and configured to rotatably support the shaft portion by the bearing in a case where the roll holding unit is mounted on the printing apparatus;
• a contact member provided to the core portion and configured to be able to be put in contact with an inner wall surrounding the hollow portion of the core pipe;
• and
• a cam member disposed inside the core portion and configured to rotate about the rotation axis between a first position in which the contact member is pressed onto the inner wall and a second position in which the contact member is retracted from the inner wall.