Disclosed are an arc-drawing assisting apparatus and a tape measure including the arc-drawing assisting apparatus. The an arc-drawing assisting apparatus, which is disposed at a tape of a tape measure so as to allow a user to draw a circle or an arc by using the tape measure, includes an upper case having a graduation checking part for checking graduations of the tape, the graduations checking part being formed at one surface of an upper portion of the upper case and a center adjusting member which is rotatably assembled with the upper case and includes a lower case having an assembling protuberance, which has a center fixing pin protruding downward, formed at a lower end of the lower case. The an arc-drawing assisting apparatus includes a center adjusting member, which is movably disposed at a tape having graduations formed thereon and is also fixed in the tape when an arc is drawn, a center adjusting assisting member, which is assembled with the center adjusting member and has an angle indicator, and a writing instrument fixing member allowing a writing instrument to be fixed to a front end of the tape so that a circle and an arc in an accurate dimension can be drawn, and they can be drawn at a desire angle.