A mode dial device is set in an electrical device. The mode dial device includes a rotary member and a pressure detection module. The rotary member includes a main body, a shaft portion connecting the main body and the electrical device, and a contact portion located at the bottom of the main body with an inclined surface. The pressure detection module is electrically coupled to the electrical device and located under the rotary member. The pressure detection module includes a button portion which is movable vertically. The button portion contacts the contact portion. When the rotary member is rotated, the contact portion pushes the button portion of the pressure detection module. The pressure detection module outputs a signal according to a moving distance of the button portion.