A semiconductor device structure is provided. The semiconductor device structure includes a first fin structure over a substrate, a second fin structure laterally spaced apart from the first fin structure, a first fin spacer and a second fin spacer alongside the first fin structure, a third fin spacer and a fourth fin spacer alongside the second fin structure, and a source/drain structure. The source/drain structure includes a first lower portion between the first and second fin spacers, a second lower portion between the third and fourth fin spacers and an upper portion protruding from tops of the first to fourth fin spacers. The semiconductor device structure further includes a salicide layer extending continuously from a side of the first fin spacer to a side of the fourth fin spacer and along a first surface of the upper portion of the source/drain structure.