To provide a photo printer capable of revising a display form of thumbnails corresponding to photo images read from a medium in response to a progress state of photo printing and to provide a display control method thereof.

A PC 6 captures a photo image recorded on a medium 3 and gives it to an in-medium data analysis section 7 via a medium reader 2, displays a thumbnail list of the captured photos on an operation / display section 1, when a user 13 selects a thumbnail to be printed and starts photo printing, a printer supervisory section 15 monitors a photo print state in a printer 5, and a display data generating section 8 generates display data of a printing state of the thumbnails, a print object, end of print and the number of printouts which are emphasized in real time on the basis of a supervisory result and print designation information 40 stored in a storage section 14 and outputs the data to the operation / display section 1.