More particularly, it relates to a phenoxyacetic acid compound of the formula: ##STR2## wherein Ring A is phenylene group or a phenylene group having 1 to 2 substituent(s) selected from a lower alkyl group, a lower alkoxy group and a halogen atom; either one or two group(s) of R1, R2, R3 and R4 is/or are a lower alkyl group, and the other groups are hydrogen atom; R5 is phenyl group or a phenyl gr