To provide a spiral antenna capable of suppressing interconnection between a plurality of spiral elements in the spiral antenna having the plurality of spiral elements on a dielectric substrate.

A plurality of spiral elements 1 and 2 which are composed of a plurality of spiral conductors 1a and 1b, and 2a and 2b and have feeding points 5a, 5b and 6a, 6b in the central parts of the conductors 1a, 1b and 2a, 2b are formed on a dielectric substrate 7. Parasitic conductor loops 3 are formed in spaces on the substrate 7 between the adjacent spiral elements 1 and 2, and radio wave absorbers 8 are applied onto the loops 3.