A digital micrometer comprising: a main-body frame including an U-shaped frame part including an anvil provided on an inner side of one end of the U-shaped frame, and a spindle holding part being provided on the other end side of the U-shaped frame part and having a length in an axial direction; a spindle held by the spindle holding part, provided to be movable forward and backward in the axial direction, protruding from one end of the spindle holding part, and including a contactor on one end face; a thimble part configured to convert rotational operation into linear motion of the spindle, one end of the thimble part being coupled on the other end of the spindle holding part; and a displacement detector configured to detect displacement of the spindle, wherein the main-body frame and the spindle are formed of a non-magnetic material, the thimble part and the displacement detector are disposed on the other end side of the spindle holding part, and the length of the spindle holding part is a predetermined value or more, such that a ferromagnetic material is usable for the thimble part and the detector, wherein the thimble part includes: an inner sleeve having a slit along an axial line and fixedly provided on the other end side of the main-body frame; and an outer sleeve fitted on the inner sleeve to be rotatable in a peripheral direction and having a spiral groove on an inner peripheral surface, the spindle includes an engaging pin, the engaging pin is fixedly provided to the spindle and engaged with the spiral groove through the slit, and the thimble part is provided on the other end of the spindle holding part, wherein the displacement detector is disposed on the other end side of the thimble part. a main-body frame including an U-shaped frame part including an anvil provided on an inner side of one end of the U-shaped frame, and a spindle holding part being provided on the other end side of the U-shaped frame part and having a length in an axial direction; a spindle held by the spindle holding part, provided to be movable forward and backward in the axial direction, protruding from one end of the spindle holding part, and including a contactor on one end face; a thimble part configured to convert rotational operation into linear motion of the spindle, one end of the thimble part being coupled on the other end of the spindle holding part; and a displacement detector configured to detect displacement of the spindle, the main-body frame and the spindle are formed of a non-magnetic material, the thimble part and the displacement detector are disposed on the other end side of the spindle holding part, and the length of the spindle holding part is a predetermined value or more, such that a ferromagnetic material is usable for the thimble part and the detector, wherein the thimble part includes: an inner sleeve having a slit along an axial line and fixedly provided on the other end side of the main-body frame; and an outer sleeve fitted on the inner sleeve to be rotatable in a peripheral direction and having a spiral groove on an inner peripheral surface, an inner sleeve having a slit along an axial line and fixedly provided on the other end side of the main-body frame; and an outer sleeve fitted on the inner sleeve to be rotatable in a peripheral direction and having a spiral groove on an inner peripheral surface, the spindle includes an engaging pin, the engaging pin is fixedly provided to the spindle and engaged with the spiral groove through the slit, and the thimble part is provided on the other end of the spindle holding part, wherein the displacement detector is disposed on the other end side of the thimble part.