Submarine pipelines should be buried to protect from damage by ships' anchors. It is a very important and difficult problem for submarine pipelines to determine the burial depth reasonably. On determining the burial depth, firstly there needs estimating the depth of penetration of anchors into silty or sandy seabottom referring to the past anchoring tests. After describing the relating items for estimating the depth of penetration of anchors such as the anchor size and weight from the vessel size, the dropping velocity of anchor on the seabottom, the value of penetrating depth of anchors is calucurated. And the value considering penetrating and dragging depth is summarized.