A detector for a measuring device comprising: a rod-shaped stylus (41; 41A) comprising a contact at a tip thereof, the contact configured to contact a measured object; a holder configured to hold a proximal end of the stylus (41; 41A); a body configured to support the holder rotatably about a predetermined rotational axis, and a sensor for detecting a rotational displacement of the holder, wherein: the detector (4; 4A) detects a displacement of the tip of the stylus (41; 41A) based on the rotational displacement of the holder, the holder comprises: an abutting member comprising a groove on which the proximal end of the stylus (41; 41A) abuts; and a biasing member positioned to face the abutting member in a direction perpendicular to an axis of the stylus (41; 41 A) and the rotational axis, for biasing the proximal end of the stylus (41; 41A) against the groove, the abutting member further comprises an extender positioned adjacent to the groove in an extending direction of the groove and on a same side of the rotational axis as the groove, the extender further extending toward the biasing member, and the stylus (41; 41 A) comprises a proximal tapered portion at the proximal end of the stylus (41; 41 A), the tapered portion extending toward a proximal most end of the stylus (41; 41A), wherein the holder is configured such that, during operation of the detector, the stylus (41; 41A) is slidable along the groove towards the rotational axis, wherein, during the sliding of the stylus (41; 41A), the tapered portion of the stylus (41; 41 A) slides up the extender to generate a force which causes the proximal end of the stylus (41; 41 A) to move towards the biasing member. a rod-shaped stylus (41; 41A) comprising a contact at a tip thereof, the contact configured to contact a measured object; a holder configured to hold a proximal end of the stylus (41; 41A); a body configured to support the holder rotatably about a predetermined rotational axis, and a sensor for detecting a rotational displacement of the holder, wherein: the detector (4; 4A) detects a displacement of the tip of the stylus (41; 41A) based on the rotational displacement of the holder, the holder comprises: an abutting member comprising a groove on which the proximal end of the stylus (41; 41A) abuts; and a biasing member positioned to face the abutting member in a direction perpendicular to an axis of the stylus (41; 41 A) and the rotational axis, for biasing the proximal end of the stylus (41; 41A) against the groove, the abutting member further comprises an extender positioned adjacent to the groove in an extending direction of the groove and on a same side of the rotational axis as the groove, the extender further extending toward the biasing member, and the stylus (41; 41 A) comprises a proximal tapered portion at the proximal end of the stylus (41; 41 A), the tapered portion extending toward a proximal most end of the stylus (41; 41A), wherein the holder is configured such that, during operation of the detector, the stylus (41; 41A) is slidable along the groove towards the rotational axis, wherein, during the sliding of the stylus (41; 41A), the tapered portion of the stylus (41; 41 A) slides up the extender to generate a force which causes the proximal end of the stylus (41; 41 A) to move towards the biasing member. the detector (4; 4A) detects a displacement of the tip of the stylus (41; 41A) based on the rotational displacement of the holder, the holder comprises: an abutting member comprising a groove on which the proximal end of the stylus (41; 41A) abuts; and a biasing member positioned to face the abutting member in a direction perpendicular to an axis of the stylus (41; 41 A) and the rotational axis, for biasing the proximal end of the stylus (41; 41A) against the groove, an abutting member comprising a groove on which the proximal end of the stylus (41; 41A) abuts; and a biasing member positioned to face the abutting member in a direction perpendicular to an axis of the stylus (41; 41 A) and the rotational axis, for biasing the proximal end of the stylus (41; 41A) against the groove, the abutting member further comprises an extender positioned adjacent to the groove in an extending direction of the groove and on a same side of the rotational axis as the groove, the extender further extending toward the biasing member, and the stylus (41; 41 A) comprises a proximal tapered portion at the proximal end of the stylus (41; 41 A), the tapered portion extending toward a proximal most end of the stylus (41; 41A), wherein the holder is configured such that, during operation of the detector, the stylus (41; 41A) is slidable along the groove towards the rotational axis, wherein, during the sliding of the stylus (41; 41A), the tapered portion of the stylus (41; 41 A) slides up the extender to generate a force which causes the proximal end of the stylus (41; 41 A) to move towards the biasing member.