To provide a bar code reader which can reduce noise caused by diffused reflected light in a case with simple constitution.

In a lower case 1a, a laser diode 3, a converging mirror 4, a galvanomirror 5, and a photodiode 6 are arranged. Irradiation windows 2a are provided in the front 11a of the lower case 1a and in the front of an upper case, respectively. As the galvanomirror 5 swings, the irradiation window 2a is scanned with laser light from one end part to the other end part. Black reflecting plates 7 are fitted on both the sides of the irradiation windows 2a in the lower case 2a and upper case while overlapping with parts wider than the irradiation windows 2a in the scanning range of the laser light. Black sponge is stuck inside the top surface of the upper case.