Latent heat storage substance, clathrate hyrate or slurry thereof, method for producing clathrate hyrate or slurry thereof, and latent heat storage agent

A latent heat storage material including a clathrate hydrate including, as its guest compound or guest compounds, a salt containing at least one of primary phosphate ion (H2PO4−), secondary phosphate ion (HPO42−) and tertiary phosphate ion (PO43−), and a pH regulator.