A kind of pen-type mobile telephone. It comprises: housing (1), display (2), button (3, 4, 5), telephone receiver (6), earphone (7), etc. It is characterized in that said pen-type mobile telephone's housing possesses slender rod-form; said display (2) is slender and in longitudinal setting; In said housing (1), also included are: printed circuit board (11), radio frequency module (12), fundamental frequency module (13), and SIM card plug & receptacle (14); said printed circuit board (11) uses more than 6 layer printed circuit board, with its width less than the width of the housing (1); widths of said radio frequency module (12) and fundamental frequency module (13) are also less than the width of the housing; socket (9) inserted with SIM card plug & receptacle is set at the side face of said housing (1), and said SIM card plug & receptacle (14) uses drawer-type SIM plug receptacle. The volume of said housing (1) is less than: length 140 mm.times.width 35 mm.times.thickness 23 mm.