The origin of the internal stress around micropipes existed in the hexagonal silicon carbide single crystals has been investigated by strain model. The model designed from acrylate resin perfectly demonstrates the strain distribution around micropipes. The strain distribution was confirmed by interference patterns observed by photoelastic measurements under the crossed polars condition. Generally it is argued that micropipes are formed by stress relaxation in the center of the screw dislocation, however, the strain model adopted demonstrates that the stress origin around micropipes occurred by the edge dislocation. Therefore, we argue that micropipes contain the mixed dislocation.