To obtain a crosslinked aliphatic polyoxamide comprising the crosslinked product of a specific aliphatic polyoxamide, capable of exhibiting excellent bioabsorbability, steam penetrability and biodegradability and useful for surgery devices such as suture, shaping devices, lubricants, etc.

This crosslinked aliphatic polyoxamide comprises the crosslinked product of an aliphatic polyoxamide having (U1) a repeating unit of formula I [X is O, a group of the formula: N(R) (R is H, a 1-8C alkyl); R1, R2 are each R; R3 is an alkylene unit, etc.,] and (U2) a repeating unit of formula II (Y is X, wherein Y and X are simultaneously not O; R17 is a 2-8C alkylene which may have an ethereal O in the chain, etc.; T is 1-2000), a repeating unit of formula III [R5 is (CH2)3-O, CH2-CH2-O-CH2, etc.; B is such a number as giving a number-average mol.wt. (Mn) of <200,000], a repeating unit of formula IV (R9 is R5; G is a residue obtained by removing 1-200 hydrogen atoms from the hydroxyl groups of an alcohol having 1-200 hydroxyl groups; P is such a number as giving an Mn <1,000,000; L is 1-200) or their combination.