A notebook-sized computer, comprising a main unit having a display screen portion with a display screen and a key input portion, said notebook-sized computer further comprising an electrostatic capacitance type input pad by which the touch operation by user's finger is detectable, a palm rest portion arranged near the electrostatic capacitive type input pad underneath which the sensor substrate of a position detection device is placed, and a position detection device comprising the sensor substrate mounted internally in said notebook-sized computer and including a plurality of loop coil groups realized by one or a plurality of patterns on the sensor substrate, each of the loop coils comprising at least one turn, a position detection circuit electrically connected to the loop coils within the sensor substrate, a position indicator having a resonance circuit coupled to said coils in electromagnetic coupling fashion, wherein the detection circuit detects operations initiated by using the position indicator when the position indicator is placed in contact with or suspended a prescribed distance above the sensor substrate.