Disclosed is a strip measuring apparatus. According to the present invention, the strip measuring apparatus comprises: an apron arranged between table rollers; a light irradiating part arranged in one side of the apron to irradiate light toward the apron; and a light sensing part arranged in the other side of the apron to sense light irradiated from the light irradiating part. The apron includes: an apron body arranged in a side of a rolling device based on a point where a strip discharged from the rolling device is fallen off, and having a light passing hole formed longer than the width of the strip; and a liner combined with the upper side of the apron body to be detached.