A laser scanner for a bar code reader has a laser source (41), a laser beam scanning means (31, etc.,) for scanning a bar code (B) on an object in a predetermined direction with a laser beam emitted from the laser source, a light emission window (25) for emitting the scanning beam toward the bar code on the object, and an optical detecting means (51) for detecting signal light reflected from the bar code. The laser beam scanning means and optical detecting means are integrally incorporated in a single substrate (20), and the light emission window is supported on the substrate by a transparent support (23, etc.).