Abstract: A taper micrometer includes a straight piece having two datum pieces for contacting a surface of a cone to establish a base line perpendicular to and passing the axis of the cone and coincident with a longitudinal axis of the straight piece, a higher contacting piece, a lower contacting piece, a higher contacting piece transporter in carrying the higher contacting piece a longitudinal groove of the straight piece and capable of movement along the longitudinal axis to contact a first point on the surface and a measuring device capable of moving the lower contacting piece along the groove to contact a second point on the surface for indicating a value which is two times the distance between the two points along the direction of the base line divided by the distance between the two points along the direction of the axis of the cone so that the value directly represents the taper of the cone.