A swing piece cancel cam for an electromagnetic needle selection apparatus S that comprises: a swing piece 6 that is swingably fitted in a swing piece base member, and that has attractive portions 6a, 6b on both end portions in a lateral direction; a main body block 20 having an active surface including attracting sections 4 that attract the attractive portions 6a, 6b by electromagnetically selecting the attractive portions; and a swing piece cancel cam 2 that is provided to the main body block and that guides the swing piece on the active surface toward the attracting section, wherein the swing piece cancel cam on the active surface has two inclined surfaces 51 each inclining to approach the opposite plane as a distance from the attracting section decreases in longitudinal direction Y, and to retract from the opposite plane as the distance from the attracting section increases in longitudinal direction Y, and the two inclined surfaces 51 gradually approaches the opposite plane from the both ends in the lateral direction X towards the center portion.