To provide a thinned key input device and a thinned computer with which any input defect hardly occurs without damaging operability.

This device is provided with a key top 11 forming a key symbol, click rubber 10 having a click rubber top part 10a for providing the key top, click rubber bent part 10b extended downward rather than the top part, click rubber flat part 10c continued from the lower end of bent part and contact pressing part 10d provided while being protruded oppositely to the top part so as to connect a contact when this bent part is bent by pressing the key top, and land part 15 provided around this key top and when the height from the flat part to the land part and the top part is defined respectively as (x) and (y), the condition of 0≤x≤y is satisfied.