A printing apparatus includes: (A) a transport mechanism transporting a medium in a forward direction and a backward direction; (B) a head printing dots on the medium; (C) a sensor sensing existence of the medium in a non-contact manner; (D) a reversion mechanism reversing the medium; and (E) a controller controlling the sensor to sense an end of the medium when the transport mechanism transports the medium in the forward direction so as to allow the head to print the dots on the surface of the medium and controlling the sensor to sense the end of the medium when the transport mechanism transports the medium in the backward direction so as to allow the reversion mechanism to reverse the medium after the dots are printed on the surface thereof.