This Shime-kazari is something Japanese people put on their doors or gates during the new year period to ward the bad spirits away. It is also a way to welcome the gods inside the house at the start of the year.
Most people go and get a shime-kazari at a temple or shrine...but these days you can also order them online. This one decorated the door of a hair salon near Tokorozawa Station. I'm always curious what people do with the orange after they take it down.
And if you're wondering about the rabbit poster in the window...2011 is the year of the rabbit!