Portable information device and cover device

The invention provides a portable information device with a cover device and the cover device, wherein the portable information device can ensure heat dissipation performance and can restrain quality reduction of appearance and touch feeling. The portable information device is provided with: a case in which a heating element is housed; and a cover device that covers the rear surface of the case, the cover device having: a core material; a graphite sheet laminated on the surface of the core material; an auxiliary sheet that is softer than the core material and that is laminated on the surface of the graphite sheet; and a surface material that is softer than the auxiliary sheet, and that forms the surface of the cover device by being laminated on the surface of the auxiliary sheet. 本发明提供能够确保散热性能，并且抑制外观、触感的品质降低的具备盖装置的便携式信息设备以及盖装置。便携式信息设备具备：壳体，在内部收容有发热体；以及盖装置，覆盖上述壳体的背面，上述盖装置具有：芯材；石墨片，层叠在上述芯材的表面；辅助片，比上述芯材柔软，且上述辅助片层叠在上述石墨片的表面；以及表面材料，比上述辅助片柔软，且上述表面材料层叠在上述辅助片的表面而形成该盖装置的表面。