This study investigates the relationship between transferred shear force and relative displacement of the shear connector in steel-concrete sandwich beam. The models, which can consider the effects of the height, thickness and shape of the shear connector, concrete strength, and thickness of the base steel plate where the shear connectors were attached, were proposed. The predicted relationship between transferred shear force and relative displacement as well as the curvature distribution along the vertical part of the shear connector are found to agree with the experimental results. Finite element analysis with the proposed model indicates its applicability as a constitutive model for shear connector.