It is one of the entry points to the Todo area of Enryaku-ji Temple complex.

With this admission fee, you can enter any of the Temple complex buildings in the Todo area, except the optional museum (extra 500JPY required).

*The entire Enryaku-ji complex is actually divided into 3 large areas: 1. Todo Area (this particular location); 2. Saito Area; 3. Yokawa Area

Keep your ticket! There are two locations that require re-entry to the Todo area from another entry point, so make sure you have your ticket to show that you got earlier.