A high-frequency-dielectric-heating-adhesive-sheet includes: a first adhesive layer containing a first thermoplastic resin; a second adhesive layer containing a second thermoplastic resin; and an intermediate layer, a ratio DPM/DP1 of dielectric property DPM of the intermediate layer to dielectric property DP1 of the first adhesive layer and a ratio DPM/DP2 of the dielectric property DPM of the intermediate layer to dielectric property DP2 of the second adhesive layer are each less than one, and the dielectric property DP1, the dielectric property DP2, and the dielectric property DPM are values of dielectric property (tanδ/ε’r) of the first adhesive layer, the second adhesive layer, and the intermediate layer, respectively. tanδ denotes a dielectric dissipation factor at 23° C. and a frequency of 40.68 MHz and ε‘r denotes a relative permittivity at 23° C. and the frequency of 40.68 MHz.