A printer includes a mainframe including a front face part that has an opening through which a recording medium passes; a guide unit connected to the mainframe on a first side of the front face part; a printer mechanism unit configured to perform printing on the recording medium, and connected to the mainframe on a second side of the front face part opposite to the first side thereof; an arm unit having a first end connected to the mainframe; and a shaft unit configured to hold a roll of the recording medium, and connected to a second end of the arm unit, wherein the guide unit is configured to guide the recording medium so as to feed the recording medium to the printer mechanism unit through the opening of the front face part of the mainframe.