A binding unit that specifically binds to fibroblast activation protein α (FAPα), a polynucleotide that encodes the binding unit, a vector that comprises the polynucleotide and a host cell, a method for use in producing the antigen-binding unit and a method for treating a disease by using the FAPα-specific binding unit; the binding unit that specifically binds to FAPα may efficiently bind to tumor cells that express FAPα, and immune effector cells comprising the binding unit exhibit significant killing capabilities against tumor cells that express FAP.