A nuclear magnetic resonance measurement apparatus comprising: a phase offset map calculator arranged to calculate a phase offset map which does not depend on a spatial distribution of an inhomogeneous magnetic field component of a static magnetic field of the nuclear magnetic resonance measurement apparatus or a phase evolution period, based on a first phase map P 1 acquired by preliminary execution of a first pulse sequence having a first phase evolution period and a second phase map P 2 acquired by preliminary execution of a second pulse sequence having a second phase evolution period longer than the first phase evolution period; a magnetic field map calculator arranged to calculate a magnetic field map which shows the spatial distribution of the inhomogeneous magnetic field component, based on a phase map acquired by execution of the second pulse sequence and the phase offset map; and an adjuster arranged to execute shimming to correct the static magnetic field based on the magnetic field map, wherein the phase offset map calculator is further arranged to calculate the phase offset map by calculating: P 2 − α P 2 − P 1 wherein α describes a ratio of the second phase evolution period to a phase evolution period difference, and the phase evolution period difference is a difference between the first phase evolution period and the second phase evolution period, and wherein the phase offset map calculator comprises: an acquirer arranged to acquire a positive-side first phase map and a positive-side second phase map by preliminarily executing the first pulse sequence and the second pulse sequence in a state where a value of a particular shim coefficient has been changed to a positive side, and that acquires a negative-side first phase map and a negative-side second phase map by preliminarily executing the first pulse sequence and the second pulse sequence in a state where the value of the particular shim coefficient has been changed to a negative side; and a ratio calculator arranged to calculate the ratio α based on the positive-side first phase map, the positive-side second phase map, the negative-side first phase map, and the negative-side second phase map. a phase offset map calculator arranged to calculate a phase offset map which does not depend on a spatial distribution of an inhomogeneous magnetic field component of a static magnetic field of the nuclear magnetic resonance measurement apparatus or a phase evolution period, based on a first phase map P 1 acquired by preliminary execution of a first pulse sequence having a first phase evolution period and a second phase map P 2 acquired by preliminary execution of a second pulse sequence having a second phase evolution period longer than the first phase evolution period; a magnetic field map calculator arranged to calculate a magnetic field map which shows the spatial distribution of the inhomogeneous magnetic field component, based on a phase map acquired by execution of the second pulse sequence and the phase offset map; and an adjuster arranged to execute shimming to correct the static magnetic field based on the magnetic field map, wherein the phase offset map calculator is further arranged to calculate the phase offset map by calculating: P 2 − α P 2 − P 1 wherein α describes a ratio of the second phase evolution period to a phase evolution period difference, and the phase evolution period difference is a difference between the first phase evolution period and the second phase evolution period, and wherein the phase offset map calculator comprises: an acquirer arranged to acquire a positive-side first phase map and a positive-side second phase map by preliminarily executing the first pulse sequence and the second pulse sequence in a state where a value of a particular shim coefficient has been changed to a positive side, and that acquires a negative-side first phase map and a negative-side second phase map by preliminarily executing the first pulse sequence and the second pulse sequence in a state where the value of the particular shim coefficient has been changed to a negative side; and a ratio calculator arranged to calculate the ratio α based on the positive-side first phase map, the positive-side second phase map, the negative-side first phase map, and the negative-side second phase map. an acquirer arranged to acquire a positive-side first phase map and a positive-side second phase map by preliminarily executing the first pulse sequence and the second pulse sequence in a state where a value of a particular shim coefficient has been changed to a positive side, and that acquires a negative-side first phase map and a negative-side second phase map by preliminarily executing the first pulse sequence and the second pulse sequence in a state where the value of the particular shim coefficient has been changed to a negative side; and a ratio calculator arranged to calculate the ratio α based on the positive-side first phase map, the positive-side second phase map, the negative-side first phase map, and the negative-side second phase map.