A periodic array of metallic In atomic chains on a Si(111) surface, 4×1-In superstructure, has been investigated by angule-resolved photoemission spectroscopy (ARPES) at room temperature and 100 K, and by scanning tunneling microscopy (STM) at 6 K. We have found from ARPES measurements a one-dimensional metallic band folding back at 100 K and leaving an energy gap at Fermi level. This leads to a metal-to-insulator phase transition and thus supports the charge-density-wave (CDW) model rather than an order-disorder model for the 4×1 (room temperature) to 8×'2' (low temperature) phase transition. We also have found a CDW-lattice locking effect from STM observation at 6 K, that is a lack of one-to-one correspondence between the filled- and empty-state images. The effect is interpreted that the CDW is pinned on the frozen lattice in two different ways. Furthermore, dynamics of a highly movable soliton in the CDW has been observed, which is a characteristic of this kind of quasi-one-dimensional systems.