PURPOSE: To improve the using efficiency of a recording light by immediately applying the recording light emitted from a light source for recording information consisting of a laser diode through an optical member having a polarizing plane on an optical card.

CONSTITUTION: The recording light L1 emitted from the laser diode 1 is made parallel by a collimator lens 2, thereafter, passed through a polarizing beam splitter 3 and a converging lens 4 and is applied on an information recording medium 10 to form a first beam spot SP1. This beam spot SP1 produces a thermally irreversible change in the information recording medium 10 to form a pit, thereby, the information is recorded. In this case, since a non-polarizing beam splitter is not present in the projection path of the recording light L1, the using efficiency of the recording light L1 in a projection system A1 becomes better about two times than the conventional example.