An electronic apparatus includes the following: a heat dissipation chamber that is formed by liquid tightly separating the inside of a main unit case with a partition, has an inlet air vent and an outlet air vent in the partition, and includes a heat dissipation portion; a cooling fan that is located in the heat dissipation chamber; an inlet that is provided in the main unit case to introduce outside air into the heat dissipation chamber through the inlet air vent; and an outlet that is provided in the main unit case to exhaust an air flow sent from the cooling fan to the outside through the outlet air vent. An air channel that extends from the inlet air vent through a side wall of the main unit case to communicate the heat dissipation chamber with the inlet is liquid tightly sealed from the internal space of the main unit case with a sealing wall. A plurality of plate-shaped ribs are provided in the air channel so as to extend in a flow path direction and arranged in a lateral direction of the inlet air vent. The rigidity of the main unit case can be ensured sufficiently while maintaining the liquid tightness between the inside of the main unit case and the heat dissipation chamber.