A heat storage apparatus according to the present disclosure includes a heat storage material and a member. The heat storage material forms a clathrate hydrate by cooling. The member has a surface with a plurality of holes. In the case that the lattice constant of the clathrate hydrate is denoted by L and the outside diameter of a cage included in the clathrate hydrate is denoted by D, the plurality of holes are spaced at intervals of 1L to 10L, and each of the plurality of holes has a hole diameter of 1D to 20D.