Muscle stiffness occurs frequently after various physical exercises. It is palpable but is not expressed quantitatively. Acupuncture needling is known to be effective in reducing post-exercise muscle stiffness and pain. The present study was undertaken 1) to find suitable equipment to measure the degree of muscle hardness, and 2) to examine acupuncture needling effect on muscle stiffness. For this purpose we devised a new muscle hardness meter. Bilateral triceps surae muscles (TSM) of 30 male volunteers were loaded for 20 min by repeatedly standing on tiptoe at the edge of a table. The hardness of the bilateral TSM was increased 20% after exercise, but this increase was significantly (p<0.05) diminished by acupuncture needling immediately after the exercise. Sixty percent of the volunteers reported that the degree of pain was lower in the acupuncture needled side than in the control side. It was concluded that the muscle hardness meter was useful for quantitative analyses of muscle stiffness, and acupuncture needling was effective in reducing post-exercise muscle stiffness and pain.