The present invention has its object provision of polylactic acid resin expanded beads having a controlled crystalline state and exhibiting excellent fusion bonding at the time of in-mold molding. The expanded beads 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 a fusion peak with a peak temperature that is on a higher temperature side than the reference peak temperature and another fusion peak with a peak temperature that is on a lower temperature side than the reference peak temperature.