To improve attenuation characteristics of a band pass filter on a high frequency side other than a pass band by devising the shield case structure of the band pass filter.

In the band pass filter configured of a substrate 100 configured by disposing resonance elements 150a-150f each formed of a microstrip line at predetermined intervals and a shield case 200 surrounding the substrate 100, the shield case 200 includes: a first space portion 280 which is wider than the area where the plurality of resonance elements 150a-150f are disposed, and has a predetermined height; and a second space portion 290 which is formed continuously above the first spatial portion 280 and has a predetermined cutoff frequency. The input high frequency signal of a pass band is transmitted under a transmission mode by the microstrip line and spatial propagation caused by the waveguide mode of an input high frequency signal of a predetermined frequency or lower is suppressed.