PURPOSE: To decrease the width of a reel spring while stabilizing the welding by forming a welded part, having reel holes at two positions shifted in the breadthwise direction, in the central part of the reel spring and cutting a spring along a line extending in parallel with the breadthwise direction while passing through a positioning hole shifted in the breadthwise direction from the reel hole.

CONSTITUTION: A reel 2 or a hub applied with a tape 1 is placed rotatably in a cassette case 3. A welded part 51 having welding holes 5, 5 shifted in the breadthwise direction from the center line of the reel is formed in the centeral part of a plate reel spring 4 for urging the reel against the inner face of a case 3. A spring 4 having the end parts 41, 41 extending in the direction toward the reel center from the welded part 51 is provided with a positioning hole 8 at a position shifted from the hole 5 along the center line of the breadthwise reel 2. The spring 4 is then cut with constant with along a cut line 71 extending between the holes 8, 8 in parallel with the breadthwise direction. When the spring 4 is welded, the opposite ends 41, 41 thereof are welded on the center line of the reel 2.