Expanded composite resin beads and molded article thereof

An expanded composite resin bead, comprising a styrene resin and a propylene resin,

• wherein:
• a content of the propylene resin in the expanded composite resin bead is from 20 to 40% by mass with respect to a total of 100% by mass of the styrene resin and the propylene resin;
• a weight average molecular weight of the styrene resin is from 300,000 to 500,000;
• a plurality of disperse phases comprising the styrene resin are dispersed in a continuous phase comprising the propylene resin in a cross-section of a cell wall forming the expanded composite resin bead in a transmission electron micrograph;
• and
• an average value of maximum diameters of the disperse phases is from 0.01 to 1 μm and a value of a ratio of the average value of the maximum diameters to an average value of minimum diameters of the disperse phases is from 1 to 10.