PURPOSE:To obtain a new fluorocyclopropylaminoacrylic acid ester derivative useful as an intermediate of a compound having a quinolinecarboxylic acid skeleton and useful as a medicine, especially an antimicrobial agent CONSTITUTION:A fluorocyclopropylaminoacrylic acid ester derivative represented by formula I (X is a halogen or H; X is a halogen or H; X is a halogen; X is a halogen; X is a halogen; R is H or a lower alkyl), e.g. 3-(cis-2- fluorocyclopropylamino)-2-(2,4,5-trifluorobenzoyl)-aerylic acid ethyl ester. A compound of formula I, especially an exemplified compaund of formula VIIa (R is C2H5) is synthesized by reacting 3-ethoxy-2-(2,4,5-trifluorobenzoy1)acrylic acid ethyl ester of formula VIa with a new cis-1-amino-2-fluorocyclopropane. In addition, if the compound of formula VIIa is reacted with equimolar sodium hydride in anhydrous dioxane solvent, a compound of formula IIa is obtain. From the compound of formula IIa, a compound of formula III as an antimierobial agent can be obtained.