To provide a monitor for portable body motion, capable of recording and storing the number of steps between arbitrary points in time and walking conditions such as running, walking, resting, etc., along with the time automatically by a body motion sensor.

This portable body motion monitor (100) comprises a means connected to a terminal (20) capable of transmitting data to and from a computer system (41) of a health care center (40) via an interface (110) to transmit data; a means for monitoring body motions to a user (10) carrying the device at all times by a built-in body motion sensor (206), and recording and storing the number of steps between certain points of time and walking conditions, such as running, waking, resting, etc., of the user and a means for transmitting data (D1) accumulated by this recording; and storing means to the terminal (20) via the interface (110).