Biodegradable aliphatic polyester-based fiber and method for producing same

The objective of the present invention is to improve the spinnability and productivity, and increase the tensile strength of a polyester-based fiber containing polyhydroxyalkanoate. This biodegradable aliphatic polyester-based fiber contains polyhydroxyalkanoate, a crystal nucleating agent, and a lubricant, wherein the crystal nucleating agent contains pentaerythritol, and the lubricant contains at least one selected from the group consisting of behenic acid amide, stearic acid amide, erucic acid amide, and oleic acid amide.