This study surveyed the relative usage, amount of food, and consumption of food of deer in three habitat types as artificial forests located more than 1 km away from an artificial grassland (hereafter FO), forest edges located within 50 m from the artificial grassland (hereafter FE), and the artificial grassland (hereafter AG). The relative usage by deer of the three habitat types was evaluated by using motion-triggered cameras, and the amount and consumption of food were evaluated through a comparison of plant biomass within and outside fences (control). The relative usage of AG was much higher than that of other habitat types except in winter. The relative usage of FO was generally lower than that of other habitat types but increased in winter. The plant biomass of control in AG was significantly lower than that of fence in AG regardless of season. The plant biomass of control in FO was significantly lower than that of fence in FO only in winter. This study showed that sika deer preferentially selected artificial grasslands but used forests in winter. The mosaic landscape of artificial grasslands and forests is the most suitable landscape for sika deer.