Intake device of internal combustion engine

An intake device of the internal combustion engine, comprising:

• an upper passage wall and a lower passage wall which are disposed next to each other in a vertical direction and are connected together to form an intake passage, wherein
• the lower passage wall has a recessed portion, which is recessed in a horizontal direction, in part of an inner surface thereof,
• in a deep portion in the horizontal direction, the recessed portion has a recessed surface to which a negative pressure outlet port for taking out negative pressure generated in the intake passage opens,
• an opening which opens upwards is provided in a position which opposes to the upper passage wall in the vertical direction at an upper portion of the recessed portion,
• the upper passage wall has a projecting portion which extends downwards towards the negative pressure outlet port and which projects into the recessed portion through the opening and
• the projecting portion is positioned between the negative pressure outlet port and the inner surface in the horizontal direction.