Solid-state lithium-ion conductor composites consisting of a low-temperature molten salt in the system LiSCN-AlCl3 and monodispersed silica particles derived from a sol-gel process were prepared. The appearance of the composites changed from viscous liquid to fine powder with the addition of 70 mass % silica particles to the molten salt. The crystallization of the molten salt causing a decrease of conductivity was prevented in a wide temperature range by the addition of silica particles. In spite of the significant change of appearance with the addition of the particles, conductivity of the composites with 70 mass % silica particles was higher than 1 x 10(-4) S cm(-1). The conductivity value of the composites was as high as that of pure molten salt. The ion-transport number of the composites was higher than 0.9999. The value obtained by dividing the de conductivity using nonblocking electrodes by the ac conductivity was 0.58, indicating that main conducting species was lithium ions.