The　drift　of　particle　guiding　centre　caused　by　curl　B　in　a　static　inhomogeneous　magnetic　field　is　investigated　by　means　of　three-dimensional　vector　arithmetic.　The　drift　related　to　the　charged　particle　velocity　perpendicular　to　the　magnetic　field　is　divided　into　two　terms,　respectively　described　by　B　curvature　and　curl　B.　Consequently　the　representation　of　curl　B　drift　in　a　toroidal　magnetic　field　is　given,　and　the　possible　effect　on　orbits　of　passing　particle　and　trapped　particle　due　to　curl　B　drift　in　a　toroidal　magnetic　field　is　discussed.　The　results　demonstrate　that　the　drift　due　to　the　charged　particle　velocity　perpendicular　to　the　magnetic　field　is　mainly　determined　by　B　curvature,　and　the　effect　of　the　curl　B　on　the　drift　is　minor.