Provided is a particle beam irradiation apparatus that can measure and display a dose two-dimensional distribution during scan with a simple configuration, while reducing degradation of a particle beam shape. The particle beam irradiation apparatus according to the present invention includes: a beam generation portion that generates a particle beam a beam emission control portion that controls emission of the particle beam a beam scanning portion that two-dimensionally scans the particle beam a sensor portion including a plurality of first linear electrodes arranged in parallel in a first direction and a plurality of second linear electrodes arranged in parallel in a second direction orthogonal to the first direction a beam shape calculation portion that calculates a center of gravity of the particle beam from a first signal output from each of the first linear electrodes and a second signal output from each of the second linear electrodes and that obtains a two-dimensional beam shape of the particle beam around the center of gravity a storage portion that accumulates and stores the two-dimensional beam shapes and a display portion that displays the two-dimensional beam shapes as a two-dimensional distribution of a dose.
