A method of manufacturing a thermal head, comprising the steps of: bonding a support substrate and an upper substrate, which have a flat shape, together in a laminated state, the support substrate and the upper substrate having opposed surfaces, at least one of which includes a concave portion; thinning the upper substrate bonded onto the support substrate; a measurement step of measuring a thickness of the thinned upper substrate; determining a target resistance value of a heating resistor from the following expression based on the measured thickness of the upper substrate; and forming the heating resistor having the target resistance value at a position opposed to the concave portion, Rh=R0×(1+(D1+D0)/(D0+K)) where Rh represents the target resistance value; R0, a design resistance value; D1, the thickness of the upper substrate; D0, a design thickness of the upper substrate; and K, a heating efficiency coefficient.