A cast titanium slab comprising industrial pure titanium, wherein: an [alpha]-phase stabilizing element, a neutral element, or one or more types of elements selected therefrom are added to a surface serving as a rolling surface; a melted-resolidified layer obtained by melting and resolidifying has a depth in the range of 1mm or more; and the average concentration of the sum of the [alpha]-phase stabilizing element and the neutral element in the range up to a depth of 1mm, in comparison to the concentration of the sum of the [alpha]-phase stabilizing element and the neutral element in the base material, in mass%, is higher by at least 0.1% and less than 2.0%.