Polyamide pre-expanded particles of this disclosure have a peak temperature of a maximum endothermic peak of 150-275° C. on a DSC curve obtained while being heated from 30° C. to 280° C. at a heating rate of 10° C./min using a DSC. The width of the peak is 30-80° C. when a straight line approximating the DSC curve on a high-temperature side relative to the peak after an end of melting is used as a baseline. The width corresponds to a difference between an extrapolated melting start temperature which is a temperature at an intersection point between a tangent line at an inflection point of the peak on a low-temperature side and the baseline, and an extrapolated melting end temperature which is a temperature at an intersection point between a tangent line at an inflection point of the peak on a high-temperature side and the baseline.