A tablet PC capable of providing continuous utilization of a sound signal collected from a microphone without requiring any user intervention when a use mode thereof has been changed from a PC use mode to a tablet use mode is disclosed. The tablet PC includes a set of microphones to form a microphone array. The tablet PC is able to operate in a sound emphasis mode wherein sound signals collected from the microphones are processed while forming an emphasis space, and to operate in a non-processing mode wherein the sound signals are processed without forming the emphasis space. When a user manipulates a chassis orientation of the tablet PC from a PC use mode to a tablet use mode, the tablet PC operates to process the emphasis space so that the sound signals collected by the microphones can be utilized in the tablet use mode.