This article deals with the detection of pedestrians by means of a laser sensor. This sensor placed on the front of a vehicle collects information about distance distributed according to 4 horizontal planes. In order to improve the robustness of pedestrian detection using a single laser sensor we propose here a detection system based on decentralized fusion of information located in the 4 horizontal laser planes. A Parzen kernel method is described and allows to extract "pedestrian objects" in each laser layer before to carry out a decentralized fusion based also on the Parzen kernel method. Many experimental results validate and show the relevance of our pedestrian detection algorithm in regard to a method using only a single-row laser-range scanner.