A measurement method of measuring a volume of a drug filled in a needle-shaped recess of a mold in which a plurality of needle-shaped recesses that are inverted types of a micro-needle are formed, the measurement method comprising: a reference surface height acquisition step of acquiring a reference surface height that is a height between a reference surface being a first surface on the side on which the drug is filled in the mold, and a second surface opposite to the first surface; a detection result acquisition step of acquiring a first detection result obtained by detecting by means of a detection unit, for each needle-shaped recess, a reflected measurement wave emitted from a drug surface that is a surface of the drug according to incidence of the measurement wave from an incidence unit on the drug in the needle-shaped recess; a first height detection step of detecting, for each needle-shaped recess, a first height (Hb) between the reference surface and the drug surface on the basis of the first detection result acquired in the detection result acquisition step; a second height detection step of detecting, for each needle-shaped recess, a second height (Ht) from the second surface to the drug surface, from the reference surface height acquired in the reference surface height acquisition step and the first height (Hb) of each needle-shaped recess detected in the first height detection step; and a volume calculation step of calculating, for each needle-shaped recess, the volume of the drug in the needle-shaped recess on the basis of the second height (Ht) of each needle-shaped recess detected in the second height detection step and a known shape of the needle-shaped recess, wherein the method further comprises: a first incidence step of causing the measurement wave to be incident on the drug surface in each needle-shaped recess; and a first detection step of detecting, for each needle-shaped recess, the reflected measurement wave emitted from the drug surface according to the incidence of the measurement wave in the first incidence step, wherein the detection result acquisition step includes acquiring the first detection result of the measurement wave detected in the first detection step, wherein the reference surface height is a thickness of the mold, the reference surface height acquisition step includes acquiring a second detection result obtained by detecting the reflected measurement wave emitted from the first surface and the second surface according to incidence of the measurement wave on the non-formation region of the needle-shaped recess included in the mold, and acquiring the thickness of the mold as the reference surface height on the basis of the second detection result. a reference surface height acquisition step of acquiring a reference surface height that is a height between a reference surface being a first surface on the side on which the drug is filled in the mold, and a second surface opposite to the first surface; a detection result acquisition step of acquiring a first detection result obtained by detecting by means of a detection unit, for each needle-shaped recess, a reflected measurement wave emitted from a drug surface that is a surface of the drug according to incidence of the measurement wave from an incidence unit on the drug in the needle-shaped recess; a first height detection step of detecting, for each needle-shaped recess, a first height (Hb) between the reference surface and the drug surface on the basis of the first detection result acquired in the detection result acquisition step; a second height detection step of detecting, for each needle-shaped recess, a second height (Ht) from the second surface to the drug surface, from the reference surface height acquired in the reference surface height acquisition step and the first height (Hb) of each needle-shaped recess detected in the first height detection step; and a volume calculation step of calculating, for each needle-shaped recess, the volume of the drug in the needle-shaped recess on the basis of the second height (Ht) of each needle-shaped recess detected in the second height detection step and a known shape of the needle-shaped recess, wherein the method further comprises: a first incidence step of causing the measurement wave to be incident on the drug surface in each needle-shaped recess; and a first detection step of detecting, for each needle-shaped recess, the reflected measurement wave emitted from the drug surface according to the incidence of the measurement wave in the first incidence step, wherein the detection result acquisition step includes acquiring the first detection result of the measurement wave detected in the first detection step, wherein the reference surface height is a thickness of the mold, the reference surface height acquisition step includes acquiring a second detection result obtained by detecting the reflected measurement wave emitted from the first surface and the second surface according to incidence of the measurement wave on the non-formation region of the needle-shaped recess included in the mold, and acquiring the thickness of the mold as the reference surface height on the basis of the second detection result.