A bone biopsy device includes an outer cannula having a mouth with a cutting edge to section a frustule of spongy bone, a plate mounted slidably within the cannula and provided with a semi-cylindrical portion at its distal end, and a stylet mounted slidably within the plate and provided with a pointed tip which protrudes from the mouth of the cannula to pierce the compact part of the bone. The mouth of the cannula has on its inside a narrowing and the semi-cylindrical part of the plate has at its distal end at least one pair of opposed circumferential sets of teeth adapted to bend radially inwards when they encounter the narrowing of the mouth, to clasp the base of the sectioned frustule and allow extraction of the frustule by the plate while the cannula is kept at the operating site, allowing aspiration of marrow after the frustule has been removed.