The switching behavior in the C1-uniform (C1U), C1-twisted (C1T) and C2-uniform (C2U) states, which were observed in surface-stabilized ferroelectric liquid crystal (SSFLC) devices with the chevron layer structure, were investigated. The voltage dependence of the extinction angle was investigated in the C1U and C2U states and was discussed in terms of the switching model of these states. The boat-shape disclination loops were observed in the C1U, C1T and C2U states, suggesting that they were attributed to the molecular switching at the chevron interface. In addition, this paper describes a gray scale with smooth voltage-transmission characteristic, which were induced by the voltage dependence of the extinction angle.