An optical touch device includes a transparent substrate and at least a light emitting and receiving unit. The transparent substrate has a touch surface, a first light incidence surface and a first light emitting surface. Each light emitting and receiving unit includes a linear light source, a light path adjusting component and a light sensing component. The linear light source is disposed beside the first light incidence surface. The light path adjusting component is disposed between the linear light source and the first light incidence surface and configured for adjusting the incidence angles of the optical signals striking at the first incidence surface so that each of the optical signals enters into the transparent substrate through the first incidence surface with a predetermined angle. The light sensing component is disposed beside the first light emitting surface. The optical touch device has a high light utility efficiency.