A pulsed light waveform measurement method comprising: a time difference generation step of: spatially dispersing initial pulsed light (Lp), having a linear polarization, for respective wavelengths, inputting the initial pulsed light (Lp) after the spatial dispersion to a polarization dependent type spatial light modulator in a state where the polarization plane of the initial pulsed light (Lp) is inclined with respect to a polarization direction in which the spatial light modulator has a modulation function for a first polarization component (E MO) of the initial pulsed light (Lp), such that the first polarization component of the initial pulsed light along the polarization direction is modulated and the second polarization component of the initial pulsed light orthogonal to the first polarization component is not modulated, and combining wavelength components (Lλ 1 to Lλ 6) after modulating a phase spectrum of the first polarization component (E MO) of the initial pulsed light (Lp) along the polarization direction, to cause a time difference between first pulsed light (Lp 1) including the first polarization component (E MO) and second pulsed light (Lp 2) including a second polarization component (E NON) of the initial pulsed light (Lp) orthogonal to the first polarization component (E MO); a light detection step of irradiating an object with the first pulsed light (Lp 1) and the second pulsed light (Lp 2), and detecting light generated in the object according to overlapping of the first and second pulsed light; and an analysis step of performing the light detection step while changing the time difference between the first pulsed light (Lp 1) and the second pulsed light (Lp 2) in the time difference generation step, and obtaining a temporal intensity waveform of the first pulsed light (Lp 1) on the basis of detection results of the light detection steps. a time difference generation step of: spatially dispersing initial pulsed light (Lp), having a linear polarization, for respective wavelengths, inputting the initial pulsed light (Lp) after the spatial dispersion to a polarization dependent type spatial light modulator in a state where the polarization plane of the initial pulsed light (Lp) is inclined with respect to a polarization direction in which the spatial light modulator has a modulation function for a first polarization component (E MO) of the initial pulsed light (Lp), such that the first polarization component of the initial pulsed light along the polarization direction is modulated and the second polarization component of the initial pulsed light orthogonal to the first polarization component is not modulated, and combining wavelength components (Lλ 1 to Lλ 6) after modulating a phase spectrum of the first polarization component (E MO) of the initial pulsed light (Lp) along the polarization direction, to cause a time difference between first pulsed light (Lp 1) including the first polarization component (E MO) and second pulsed light (Lp 2) including a second polarization component (E NON) of the initial pulsed light (Lp) orthogonal to the first polarization component (E MO); spatially dispersing initial pulsed light (Lp), having a linear polarization, for respective wavelengths, inputting the initial pulsed light (Lp) after the spatial dispersion to a polarization dependent type spatial light modulator in a state where the polarization plane of the initial pulsed light (Lp) is inclined with respect to a polarization direction in which the spatial light modulator has a modulation function for a first polarization component (E MO) of the initial pulsed light (Lp), such that the first polarization component of the initial pulsed light along the polarization direction is modulated and the second polarization component of the initial pulsed light orthogonal to the first polarization component is not modulated, and combining wavelength components (Lλ 1 to Lλ 6) after modulating a phase spectrum of the first polarization component (E MO) of the initial pulsed light (Lp) along the polarization direction, to cause a time difference between first pulsed light (Lp 1) including the first polarization component (E MO) and second pulsed light (Lp 2) including a second polarization component (E NON) of the initial pulsed light (Lp) orthogonal to the first polarization component (E MO); a light detection step of irradiating an object with the first pulsed light (Lp 1) and the second pulsed light (Lp 2), and detecting light generated in the object according to overlapping of the first and second pulsed light; and an analysis step of performing the light detection step while changing the time difference between the first pulsed light (Lp 1) and the second pulsed light (Lp 2) in the time difference generation step, and obtaining a temporal intensity waveform of the first pulsed light (Lp 1) on the basis of detection results of the light detection steps.