Changes in flow pattern were investigated for a viscoelastic fluid (polyethylene oxide) in various-sized micro-fabricated planar 4:1 contraction channels. The flow pattern changed from a Newtonian-like flow to a flow with a vortex growth region, during which a divergent flow and lip vortex were also observed depending on the elasticity number (El) and aspect ratio. When the aspect ratio was large, the lip vortex was observed only in a limited number of cases, and the flow pattern occurring before the vortex growth was more diverse. When the elasticity number was large, the divergent flow was not observed unlike the cases in which the Elasticity number was small. The flow pattern in the contraction microchannel was found to be diverse and abundant depending on the aspect ratio and elasticity number.