To provide a post cap mountable after the installation of a post in the construction field and hardly coming off after mounted.

The post cap 1 comprises a head part 6 concealing the upper end of the post 1, and a suspending portion 8 inserted into the post. The suspending portion 8 is formed with a storage groove 81 for storing a through-bolt 4 penetrating the post 1 in a lateral direction. The storage groove 81 is provided with a bolt storage part 83 extended in the inner part of an insertion port 82 for inserting the through-bolt 4 from the side, and vertical ribs 84 that can abut on the inner peripheral surface of the post 1 are provided on both sides of the storage groove 81. Deformable parts 85 pressed and deformed to guide the through-bolt 4 to the bolt storage part 82 when the through-bolt 4 is inserted into the insertion port 82 from the side, are formed between the insertion port 82 and the vertical ribs 84.