A mobile information apparatus having first and second operation modes includes upper, middle, and lower bodies of equipment arranged in layers, a hinge for pivotally connecting the upper body of equipment to the middle body of equipment so that the upper and middle bodies of equipment have folded and unfolded positions, a hinge for pivotally connecting the middle body of equipment to the lower body of equipment so that the middle and lower bodies of equipment have folded and unfolded positions, a first operation switch mounted on at least one of the upper body of equipment and the middle body of equipment and allowing the mobile information apparatus to operate in the first operation mode when the upper and middle bodies of equipment are in the unfolded positions, and a second operation switch mounted on at least one of the middle body of equipment and the lower body of equipment and allowing the mobile information apparatus to operate in the second operation mode when the middle and lower bodies of equipment are in the unfolded positions.