A reel device includes a reel rotatably supported in a casing of a blind. A guide is mounted on an end of the reel. The guide includes an abutting point against which a cord of the blind abuts. The guide further includes an extension extending toward the other end of the reel. A line passing the abutting point and an end edge of the guide is at an acute angle with a line orthogonal to a longitudinal axis of the reel. When a section of the cord reaches the abutting point and the end edge of the guide, an acute angle is created, and this acute angle of the section of the cord avoids two forces that act on the cord in opposite direction from acting on the same line. Thus, overlapping of the turns of the cord on the reel is avoided.