A sampling method includes: obtaining topographical information about a predetermined wide area by using a first sensor on a work machine; selecting a candidate area within the wide area, the candidate area is less than an area of the wide area, and setting a movement route based on the information about the wide area, the movement route allows a distal end portion of an arm provided on the work machine to reach a preparation position without coming into contact with an obstacle, the preparation position being located above the candidate area; moving the distal end portion of the arm along the movement route to the preparation position, and obtaining topographical information about the candidate area by using a second sensor on the distal end portion of the arm; and specifying a sampling point based on the information about the candidate area and performing sampling at the specified sampling point.