One of major research issues associated with 3D range acquisition is the creation of sensor systems with various functionalities and small size. A variety of machine vision techniques have been developed for the determination of 3D scene geometric information from 2D images. As one of active sensors, structured lighting method has been widely used because of its robustness on the illumination noise and its extractability of feature information of interest. As one of passive sensors, stereo vision does also due to its simple configuration and easy construction. In this work, we propose a novel visual sensor system for 3D range acquisition, using active technique and passive one simultaneously. The proposed sensor system includes inherently two types of sensors, an active trinocular vision and a passive stereo vision. In the active vision part of this sensor, the structured lighting method using multi-lasers is basically utilized. In its stereo vision part, a general passive stereo is constructed. Since each of them has its own advantages and disadvantages on the measurements of various objects, we propose sensor fusion algorithms for acquiring more reliable range information from them. To see how the proposed sensing system can be applied to real applications, we mount it on a mobile robot, and a series of experimental tests is performed for a variety of configurations of robot and environment. The sensing results are discussed in detail.