It is well known that sunflower (SF) sprout has more beneficial effects than SF seed due to increased levels of phytochemical components such as vitamins, total phenolics, and isoflavones during germination. This study investigated the physicochemical properties and antioxidative activities of SF seed during both germination and cultivation. In a proximate analysis, the water content of SF groat was 9.17% and then increased to 15.32% on the 11th day after seeding. On a dry weight basis, crude fat content decreased while the contents of carbohydrates, crude protein, and crude ash increased. As cultivation proceeded, the contents of minerals were in decreasing order of K, Mg, Ca, Na, Zn, Fe, Mn, and Cu, in which SF sprout cultivated for 9 or 11 days contained the highest mineral contents. Though vitamin C was not detected on SF groat, the content of vitamin C continuously increased up to the 5th day of cultivation and then decreased gradually. Vitamin E content in SF groat was higher than that in SF sprout. It was also found that the vitamin E content in SF sprout was the highest on the 5th day of cultivation. Daidzin was not detected in SF groat, but its concentration reached a maximum on the 5th day of cultivation in SF sprouts. Furthermore, higher amounts of daidzein were observed on the 3rd, 5th, and 9th days of cultivation. The highest total isoflavone content was observed on either the 3rd or 5th day of cultivation. The highest content of total phenolics was observed on the 5th of cultivation. When DPPH radical and peroxyl radical scavenging activities of SF sprout were measured in order to measure antioxidant efficacy, it was found that 5 day-cultivated SF sprout had the highest scavenging activities. In conclusion, SF sprout cultivated for 9 or 11 days was found to be a good source of minerals. Furthermore, the fifth-day after seeding was the optimal time for the production of SF sprout with effective natural antioxidant activity and high amounts of functional components such as vitamins, total phenolics, and isoflavones.