The present tourmaline treatment device includes a housing, and a container disposed in the housing so as to partition the inside of the housing into an upstream space and a downstream space and contain tourmaline granules. The container includes an upstream partition wall facing the upstream space and a downstream partition wall facing the downstream space. The upstream partition wall is provided with a plurality of inflow holes for introducing cooling water into the container from the upstream space, and the downstream partition wall is provided with a plurality of outflow holes for allowing cooling water to flow out from the container into the downstream space. The container further includes flow velocity control means for increasing flow velocity of cooling water passing through the inside of the container.