This is one of the guardians of the Chanoki Inari Shrine. This shrine is located within the Ichigaya Kamegaoka Hachimangu grounds, which is the main shrine. If you look at the photo below, you can see red lanterns on the top left corner, which is where this shrine is located.
Chanoki Inari Shrine is said to be the first shrine that was made by Kukai, a famous Japanese monk, when he first came to the Kanto area about 1,000 years ago. There are many tea bushes around this shrine, which Kukai brought as medicine from China.
It's said that this shrine has the power to heal eyes. The legend goes...one day the white fox, one of the guardians of the shrine, accidentally poked its eye with a branch of a tea bush and hurt it. When it washed its eye with the water from the holy spring, it was healed. And although this spring is no longer in use, many people come here to pray for healthy eyesight to this day.