Resin flux solder paste and mount structure

A resin flux solder paste comprising:

• a solder powder;
• and
• a flux,
• wherein the flux contains at least an epoxy resin, a curing agent, a curing accelerator, and an activator,
• the activator is a compound having a metal oxide film removing function,
• the epoxy resin contains 10% to 90% by weight of one or more of a biphenyl aralkyl type epoxy resin, a naphthalene type epoxy resin, and a dicyclopentadiene type epoxy resin, having an epoxy equivalent of 200 to 400, with respect to a total amount of the epoxy resin, and
• the curing agent contains 30% to 95% by weight of a biphenyl aralkyl phenol resin having a hydroxyl group equivalent of 150 to 350 with respect to a total amount of the curing agent, and 5% to 70% by weight of a phenol novolac resin having an allyl group having a hydroxyl group equivalent of 100 to 200 with respect to the total amount of the curing agent.