A medical apparatus main body such as a capsule main body inserted in the body cavity includes a thrust generating mechanism such as a spiral projection. The medical apparatus main body further forms an information providing unit comprising at least one of a storing unit for storing a state of the thrust generating mechanism and a direction detecting unit for detecting the direction of the medical apparatus main body. An input unit instructs a thrust generating direction of the thrust generating mechanism and thus a control unit changes continuously or the like a thrust generating state of the thrust generating mechanism based on information from the information providing unit.
