Synthetic resin welded body and method of manufacturing the same

A synthetic resin welded body comprising:

• a first synthetic resin part including a welding portion which is formed in a protruding shape and which has a top portion serving as a welding face;
• a second synthetic resin part which includes a welded face for coming in contact with the welding portion and which is welded to the first synthetic resin part by welding of the welding portion and the welded face to each other;
• and
• a groove portion which is formed along an outer peripheral face of the welding portion.

A method of manufacturing a synthetic resin welded body comprising:

• an absorption-side synthetic resin part preparing step of preparing a laser light absorbing absorption-side synthetic resin part including a welding portion which is formed in a protruding shape and which has a top portion serving as a welding face;
• a transmission-side synthetic resin part preparing step of preparing a laser light transmissive transmission-side synthetic resin part including a welded face in a position corresponding to the welding portion;
• a disposing step of disposing the absorption-side synthetic resin part and the transmission-side synthetic resin part so that the welding face comes in contact with the welded face;
• and
• the laser welding step of radiating the laser light to the welding portion from a side of the transmission-side synthetic resin part to melt the welding portion to thereby weld the absorption-side synthetic resin part and the transmission-side synthetic resin part to each other at the welding face and the welded face to obtain the synthetic resin welded body,
• wherein the recess/recesses is/are formed in the absorption-side synthetic resin part and/or the transmission-side synthetic resin part so that a groove portion is formed along an outer peripheral face of the welding portion when the absorption-side synthetic resin part and the transmission-side synthetic resin part are disposed so that the welding face comes in contact with the welded face in the disposing step.