Metals with a hexagonal closed packed (HCP) structure show creep behavior at ambient temperature. Features of this phenomenon are: (1) it appears in all and only HCP structure metals and alloys; (2) dislocations are contributing; and (3) it shows very low apparent activation energy (ca. 10 kJ/mol). Transmission electron microscope (TEM) observation was conducted on crept specimens of commercially pure Ti (CP-Ti), pure Mg, and Zn. Results showed no dislocation tangle. The dislocation arrays were aligned straightly inside the grain. The dislocation array consisted of one dislocation type. One slip system was activated in the ambient temperature creep condition. Therefore, it was considered that work hardening does not occur, and that creep deformation continued.