The present invention provides a portable computer in which an increase in temperature of a housing is suppressed. In the present invention, a guide plate is provided to suppress an increase in temperature of a bottom surface. When a cooling fan device operates, outside air taken in from inlet openings flows as an air current through a narrow flow path formed between the guide plate and the bottom surface. A flow velocity of the air current can be increased by narrowing the flow path, and heat exchange with the guide plate can be effectively performed, thereby sufficiently cooling a cooling surface. The cooled guide plate cools an air layer between the guide plate and the heat sink and thermally insulates between the air layer and the bottom surface.