Based on information recorded on and read out from a card, a card printer erasably writes information on the card or erases information recorded on the card. The card printer comprises transport means T for transporting card 70 along a passageway 5 having an inlet 4, reading means R provided in the vicinity of passageway 5 for reading out information recorded on a surface of card 70 transported along passageway 5, printing means P for recording information on and erasing information from the surface of card 70, and control means IC electrically connected to transport means T, reading means R and printing means P for determining whether to record information on or to erase information from surface of card 70 and for controlling operation of transport means T and printing means P depending on information forwarded from reading means R.