[en] The longitudinal magnetic field (LMF) state, in which the magnetic field is applied parallel to the applied current direction and ab-plane of SmBa₂Cu₃O_y (Sm123) films with shaped artificial pinning centers (APCs) of various shapes is investigated. The in-field critical current density (J _c) of pure Sm123 films in the LMF state and films with Y₂O₃, Sm₂BaCuO₅, BaHfO₃, and a multilayered structure with short BaHfO₃ nanorods were measured in the configuration. The measurement revealed that there was significant J _c enhancement only in the multilayered film. From the viewpoint of flux pinning, 3D flux pinning is key to improving in-field J _c in the LMF state. However, the Sm123 films with APCs, such as Y₂O₃ and Sm₂BaCuO₅, did not have a larger J _c than the pure Sm123 films in the LMF state. This indicates that the APCs prevent the current flowing along the external magnetic field. Both of the 3D flux pinning and the pure layer in which current can flow without disturbance are important for the J _c enhancement in the LMF state. (paper)