A method of manufacturing a thermal head, comprising: forming a concave portion opened in one surface of a support substrate and an upper substrate to be disposed on the support substrate in a stacked state, the support substrate and the upper substrate each being of a plate shape; a step of measuring a width dimension of the concave portion formed in the concave portion forming step; bonding the support substrate and the upper substrate to each other in the stacked state so as to close an opening of the concave portion; thinning the upper substrate bonded onto the support substrate in the bonding, to a thickness set based on the width dimension of the concave portion measured in the measuring; and forming a heating resistor on a surface of the thinned upper substrate in a region opposed to the concave portion.