Polylactic acid resin expanded beads exhibiting excellent fusion bonding at the time of in-mold molding have such a crystal structure that gives a first time DSC curve when heated according to heat flux differential scanning calorimetry referenced in JIS K7122(1987) and a second time DSC curve when thereafter cooled and then again heated, the second time DSC curve having a fusion peak having a reference peak temperature and the first time DSC curve having at least one fusion peak with a peak temperature higher than the reference peak temperature and another at least one fusion peak with a peak temperature not lower temperature than the reference peak temperature.