Abstract: Disclosed are an antibody to human programmed cell death 1 (PD-1) or an antigen-binding fragment thereof, a nucleic acid encoding the same, a vector including the nucleic acid, an isolated cell transformed with the vector, a method for producing the antibody or an antigen-binding fragment thereof, and a composition for preventing or treating cancer containing the same. The novel antibody binding to PD-1 or an antigen-binding fragment thereof can bind to PD-1 and inhibit the activity of PD-1, thus being useful for the development of immunotherapeutic agents for various diseases associated with PD-1.