To easily and accurately print information (image information, character information or the like) recorded in an optical disk in the loaded state of the optical disk in an information recording/reproducing device without staining the surroundings.

The information recording/reproducing device 10 includes a recording/reproducing section 14 and a printing section 18. The printing section 18 includes a printing head 54 arranged to face the printable surface 16 of an optical disk loaded in a rotary driving section 24, a head moving mechanism 60 for moving the printing head 54 in the diameter direction of the optical disk 12 along a surface 66 almost parallel to the printable surface 16 of the optical disk 12, a second video memory 120 for temporarily holding printing information, and a second control unit 64 for controlling the reading speed of the printing information from the second video memory 120 on the basis of at least rotational speed information from the rotary driving section 24 and positional information of the printing head 54.