A radical-polymerizable acrylic insulating adhesive for NCF-bonding an electronic part to a circuit board includes a (meth)acrylate monomer, a film-forming resin, an inorganic filler, a silane coupling agent, and a radical polymerization initiator. The amount of the inorganic filler is 70 to 160 parts by mass with respect to a total of 100 parts by mass of the (meth)acrylate monomer and the film-forming resin. A radical polymerization cured product of the acrylic insulating adhesive exhibits a glass transition temperature of 150 to 185° C., a linear expansion coefficient (α1) of 30 to 35 ppm in a temperature range that is lower than the glass transition temperature, and a linear expansion coefficient (α2) of 105 to 125 ppm in a temperature range that is equal to or higher than the glass transition temperature. Further, α2/α1 is greater than or equal to 3.4.