To provide a portable engine starter starting the engine of a driving device with a battery run out even if electric power is not previously reserved.

This portable engine starter includes: a pair of connection terminals connected to both the electrode terminals of the battery B incorporated in the driving device; a capacitor 13 arranged between the pair of connection terminals and charged with electric power supplied from the battery B; a current limiting section 14 arranged between one of the connection terminals and the one end of the capacitor 13 and limiting a rush current when charging the capacitor 13; and an electric power supply line 15 connected in parallel to the current limiting section 14 and supplying electric power discharged from the capacitor 13 when starting the engine.