Disclosed is a radome 1 for vehicle-mounted radar devices including a base body 2 having an electromagnetic wave permeable substrate 3 and a heater wire 41 laminated on an inner surface side of the substrate 3 and wired in a surface direction of the substrate 3, in which linear portions 411 of the heater wire 41 are arranged side by side at intervals in the surface direction of the substrate 3 in an electromagnetic wave irradiation region R of the substrate 3, and a surface occupancy ratio of the linear portions 411 of the heater wire 41 in the electromagnetic wave irradiation region R of the substrate 3 is set to 1% or more and 24% or less. It is possible to exhibit a practical snow-melting function as a radome for vehicle-mounted radar devices while suppressing attenuation of electromagnetic waves irradiated by a vehicle-mounted radar device within an allowable range.