To provide a pasturing managing device and a pasturing managing system using the device, by which not only the walking state or the standing still state of a pastured animal but also the sleeping state or the running state of it are judged to manage the health state of it such as a disease of an estrus, with excellent precision.

The pasturing managing device is provided with an acceleration sensor 11 for detecting the acceleration of mutually orthogonal three axes so as to output respective kinds of acceleration data, a data memory 12 for storing respective kind of acceleration data by time sequence and an analyzing part 13 which is connected to the data memory so as to analyze respective kinds of acceleration data and also is constituted by permitting the analyzing part 13 to be mounted on the pastured animal so as to output a state signal indicating at least the sleeping state or the running state of the animal 2 at every prescribed time.