Abstract: A drafting device includes a pair of magnetic boards securely mounted to upper and lower surfaces of a base frame respectively, a ruler movably engaged on the magnetic board, a pair of cavities defined in each of the four corners of the lower surface of the base frame, and a protrusion being formed between the pair of cavities. A guiding member is securely mounted to each of the four corners of the base frame and includes a locking block having a first wall member and a second wall member mounted on the upper and lower surfaces of the base frame respectively, a slot being defined in the second wall member through which the protrusion is received, a recess defined in an underside of the locking block between the first and second wall members and having a width equal to the distance between a bottom face of the cavity and the upper surface of the base frame. A guiding line loops around each of the guiding members and passes through two ends of the ruler.