To provide pre-foamed particles formed from a polypropylene-based resin composition containing a melt tension-improving agent improving the foam moldability of a polypropylene-based resin.

The pre-foamed particles are obtained by using a polypropylene-based resin composition including 99-55 wt.% of a polypropylene-based resin and 1-50 wt.% of a melt tension-improving agent for a polypropylene-based resin, which is formed from a polyethylene-based resin satisfying following (A) to (F). (A) The density (d) is 920-970 kg/m3. (B) The melt flow rate (MFR) measured at 190°C and a load of 2.16 kg is 1-20 g/10 min. (C) The number of terminal vinyl is ≤0.2 per 1,000 carbon atoms. (D) The relation between the melt tension (MS160(mN)) measured at 160°C and the MFR satisfies MS160>90-130×log(MFR). (E) The relation between the melt tension (MS190(mN)) measured at 190°C and the MS160 satisfies MS160/MS190<1.8. (F) The relation of the activation energy (Ea(kj/mol)) of flow and the density satisfies 125-0.105d<Ea<88-0.055d.