Extrusion molding device and method for manufacturing green honeycomb molded body

An extrusion molding device (1) is provided with a first tube (10), a screw (2B) provided in the first tube (10), a second tube (50) connected to the outlet of the first tube (10), a flow adjustment plate (20) disposed between the first tube (10) and the second tube (50), and a die (90) connected to the outlet of the second tube (50). The second tube (50) comprises, in order from the first tube (10) side, a first portion (32) having a constant inner diameter, a second portion (34) having an inner diameter that decreases with increasing distance from the first portion (32), and a third portion (36) having a constant inner diameter. The second portion (34) is inseparably integrated with the first portion (32), and the third portion (36) is inseparably integrated with the second portion (34).