To provide a data input unit by which data can be easily inputted by one hand by supporting a mobile phone by a handle added to it, providing a mechanism for moving operation keys to a position corresponding to the type of usage and moving keys to a position where they can be easily depressed by only a thumb.

A mobile information apparatus such as mobile phone has a first grip means 4, alphanumeric keys 5 and a display 2. Data are inputted by pressing the alphanumeric keys 5. The apparatus is further provided with a second grip means 18. The distance of the first grip means 4 can be adjusted with respect to the second grip means 18. The alphanumeric keys 5 is placed on an operation key member which can be rotated by a hinge shaft and can be moved to a position for facilitating input operations in response to the mode of an input.