A mouse device includes a main body, an air cushion and a first hidden key. The first hidden key is located at a first side of the main body. The air cushion is located under the main body, and contactable with a working surface. The first hidden key is arranged between the main body and the air cushion. The first hidden key is not exposed outside. When the main body is leaned in a first direction and pressed down, the first hidden key is triggered to generate a first leaning signal. The first hidden key can be used to replace the key of the conventional keyboard. Due to the structure of the mouse device, the mouse device can be operated more intuitively.