Mobile electronic apparatus includes a first sensor element group G1 and a second sensor element group G2 respectively having sensor elements R1.about.R4, L1.about.L4 for detecting a contact and arranged continuously in an annular shape as a whole; and a control unit 320 capable of performing a first control in which each sensor element group is individually controlled. The control unit 320 can perform a second control different from the first control by detecting a contact detection started by a sensor element in any one sensor element group, continuous contact detections by sensor elements adjacent to the start sensor element continued to end portion of the sensor to group, and then continuous contact detections from an end portion of another sensor group adjacent to the end portion of said one sensor group.