Disclosed is a phosphorus paste for diffusion that is used in continuous printing of a phosphorus paste for diffusion on a substrate by screen printing. The phosphorus paste for diffusion does not undergo a significant influence of ambient humidity on viscosity and has no possibility of thickening even after a large number of times of continuous printing. The phosphorus paste for diffusion is coated on a substrate by screen printing for diffusion layer formation on the substrate. The phosphorus paste for diffusion includes a doping agent containing phosphorus as a dopant for the diffusion layer, a thixotropic agent containing an organic binder and a solid matter, and an organic solvent. The doping agent is an organic phosphorus compound.