A printer apparatus includes a printer body including an opening part that has a protruding part, a support part including a rotary shaft and rotatably attached to the printer body to rotate about the rotary shaft, a platen unit provided in the support part, and a shaft bearing including a projecting part and rotatably supports the platen roller. The opening part receives the shaft bearing. In a state where the platen unit is installed in the printer body, the projecting part and the protruding part contact each other. In a case of removing the platen unit from the printer body, the shaft bearing and the support part rotate in a same direction.