Provided is a metal fine particle-containing composition which enables metal parts on electrical components to be joined at a relatively low temperature, and which achieves a strong joint and leaves little residual organic matter after joining. The metal fine particle-containing composition contains: metal fine particles (P1) comprising a metal element (M) having a bulk melting point of above 420DEG C, the surface of the particle being at least partially or wholly covered by a coating substance (C), and the primary particle diameter being 1 to 500nm; a low melting point metal powder (P2) comprising a metal or an alloy having a bulk melting point of 420 DEG C or lower; and an activating agent (A) which decomposes and removes the coating substance (C) from the surface of the metal fine particle (P1).