Abstract: One object of the present invention is to provide copper fine particles which have sufficient dispersibility when made into a paste and can be sintered at 150° C. or lower, the present invention provides copper fine particles, wherein the copper fine particles have a coating film containing copper carbonate and cuprous oxide on at least a part of the surface thereof, and a ratio between the following Db and the following Dv (Db/Dv) is in a range of 0.50˜0.90, Dv: an average value (nm) of the area equivalent circle diameter of the copper fine particles obtained by acquiring SEM images for 500 or more copper fine particles using a scanning electron microscope, and calculating by image analysis software, Db: a particle size (nm) of the copper fine particles obtained by measuring a specific surface area (SSA (m2/g)) of the copper fine particles using a specific surface area meter, and calculating by the following formula (1), Db=6/(SSA×?)×109 . . . (1) in the formula (1), ? is a density of copper (g/m3).

Abstract: One object of the present invention is to provide an electroconductive paste capable of forming an electroconductive film on a substrate having low heat resistance by light irradiation, having unlimited sintering conditions, excellent adhesion to a resin substrate, and capable of forming an electroconductive film having good electroconductivity, and the present invention provides an electroconductive paste wherein the electroconductive paste contains fine copper particles having an average particle diameter of 300 nm or less which is measured using SEM, coarse copper particles having an average particle diameter of 3˜11 ?m which is measured using SEM, a binder resin, and a dispersion medium, the fine copper particles includes a coating film containing cuprous oxide and copper carbonate on at least a part of the surface thereof, the ratio of the mass oxygen concentration to the specific surface area of the fine copper particles is 0.1˜1.