InGaS3 thin layers are promising nanostrures in the field of nanophotonics owing to the broad bandgap, sufficiently high refractive index and the simplicity of fabrication. Here we numerically investigate a system based on InGaS3  waveguides, standing side by side. We demonstrate the localization of the electromagnetic field inside the gap between two waveguides and obtain the refractive indices and losses for the slot waveguide modes at a wavelength of 505 nm. Transmittance spectra of considered configurations of different geometrical parameters were obtained The waveguiding cut-off related to the absorption inside the material and the delocalization of the electromagnetic field  was determined. The obtained results open the possibility for fabrication of novel photonic devices based on InGaS3 thin layers.