A tiltable headrest device is provided to suppress the occurrence of abnormal noise during rotation, to reduce the number of components and to improve appearance quality. Guide portions (12) each comprising a standing-up locking portion (12a), a falling-down locking portion (12b) and a rail portion (12c) are integrally formed on a core member (1), a coil spring (4) for urging a lateral rod (31) toward a direction approaching the guide portions (12) is provided in the core member (1). The lateral rod (31) is pressed to the guide portions (12) by the urging force of the coil spring (4) so as to be guided. Due to sliding contact between resin and metal, the occurrence of abnormal noise can be prevented.