A motion sensor which can easily and accurately detect bearing, attitude and acceleration in any of three-dimensional directions and a portable telephone using the same. The motion sensor comprises three magnetic sensing parts for detecting magnetic field strength in 3-axis directions orthogonal to one another, and three acceleration sensing parts for detecting accelerations in the 3-axis directions. Each of the acceleration sensing parts has a magnet body constituted to be able to displace depending on acceleration, and a magnet displacement detection head for detecting a displacement of the magnet body. The three magnetic sensing parts and the three magnet displacement detection heads are all made of the same type of magnetic detection elements which operate based on common operation principles. The three magnetic sensing parts and the three acceleration sensing parts are integrated into one modular package together with one electronic circuit for controlling these six magnetic detection elements.