Resonator type silencer for automotive engine

A resonator type silencer (5) connected to an air intake duct of an automotive internal combustion engine. The resonator type silencer comprises a first case (2) having an open end section (2A). A second case (3) is fabricated separate from the first case (2). The second case (3) has an open end section (3A) which is joinable with the open end section (2A) of the first case (2). The open end section (2A) of the first case (2) includes an end edge portion (P1) having a linear projection (5) extending along the end edge portion (P1). The linear projection (5) has an inclined face (6) extending along the end edge portion (P1) and sloped down in a direction toward a surface of the open end section (2A). The open end section of the second case (3) includes an end wall portion. A guide wall is integral with the end wall portion and extending along an end edge portion of the open end section.