A measuring instrument includes a main body, a stylus configured to be movable in relation to the main body, an encoder for detecting the amount of displacement of the stylus relative to the main body, a calculating section for calculating a measurement value from the amount of displacement detected by the encoder, a display section for displaying the measurement value calculated by the calculating section, an operation section for issuing a command to the calculating section, and a storage section that stores an effective measurement range larger than a lower limit and smaller than an upper limit of the movement stroke of the stylus. The calculating section makes a determination as to whether or not the amount of displacement detected by the encoder falls within the effective measurement range stored in the storage section and displays the result of such a determination on the display section.