To ventilate the inside of a shoe for preventing the stuffiness and bad smell of the foot inside the shoe by forming air cells in front and rear on the sole, deforming the air cells by utilizing the pressure of the user's weight applied on the sole when walking, and releasing the compressed air to the top inside the shoe.

A structure 1 comprises front air cells 4 and rear air cells 5 made of an elastic material such as rubber, communicating with each other via a ventilation passage 11. The structure 1 is disposed between an insole 2 and an outsole 3. When the pressure of the weight of a user is applied on the rear air cells 5 while the user is walking, the air cells 5 are deformed, the compressed air is sent to the front air cells 4 through the ventilation passage 11, and at the same time, an air inlet 8 is closed by the insole 2 so that the reverse air flow is prevented. Then when the pressure of the weight is applied on the front air cells 4 in the course of walking, the front air cells are deformed like the rear air cells 5, an air inlet 16 is closed, and the compressed air is released from an air outlet 15 at the top inside the shoe.