Resonant x-ray scattering experiments revealed transitional subphases near the electric-field-induced phase transition of a Se-containing chiral liquid crystal in a planar aligned cell geometry. In the lower-temperature range (Sm-C-A(*) and three-layer periodicity Sm-C-gamma(*) phases), the six-layer periodicity subphase appeared with increasing electric field during the field-induced transition from Sm-C-gamma(*) to Sm-C-gamma(*). In the higher-temperature range [four-layer periodicity antiferroelectric (AF) phase], the peak positions of the three-layer satellites shifted to those of the four-layer satellites and then the satellites corresponding to the five-through seven-layer periodicity appeared in sequence. Near the AF to Sm-C-gamma(*) a phase transition temperature, the layer periodicity increased with applied field. The molecular configurations of the subphases near the field-induced transition are discussed based on the Ising, distorted clock, and perfect clock models.