Provided is to suppress addition of configurations and to make boarding and alighting of a driver of a work machine (100, 100A) appropriate. An acquisition unit (40) configured to acquired posture information indicating a posture of the driver of the work machine (100, 100A) when boarding and alighting, a transmission unit (31) configured to transmit the posture information to an outside of the work machine (100, 100A), and a determination unit (33, 34, 211, 212) configured to determine appropriateness of the posture when boarding and alighting based on the received posture information are included to detect boarding and alighting in an inappropriate posture such as two-point support or directing a body toward the outside, make notification in a recognizable manner, and transmit to the outside of the work machine (100, 100A), so that occurrence thereof is suppressed.