There is provided a photoresist including (a) a resin composed of a polymer represented with the following general formula [1], and (b) a photo acid generator which produces acid when exposed to a light: ##STR1## wherein each of R.sup.1, R.sup.3 and R.sup.7 represents one of a hydrogen atom and a methyl group, R.sup.2 represents a hydrocarbon group including a bridged cyclic hydrocarbon group and having a carbon number in the range of 7 to 13 both inclusive, R.sup.4 represents one of a hydrogen atom and a hydrocarbon group having a carbon number of 1 or 2, R.sup.5 represents a hydrocarbon group having a carbon number of 1 or 2, R.sup.6 represents one of (a) a hydrocarbon group having a carbon number in the range of 1 to 12 both inclusive, (b) a hydrocarbon group having a carbon number in the range of 1 to 12 both inclusive and replaced with an alkoxy group having a carbon number in the range of 1 to 12 both inclusive, and (c) a hydrocarbon group having a carbon number in the range of 1 to 12 both inclusive and replaced with an acyl group having a carbon number in the range of 1 to 13 both inclusive, x+y+z=1, x is in the range of 0.1 to 0.9, y is in the range of 0.1 to 0.7, and z is in the range of 0 to 0.7. The resin has a weight percent in the range of 75 to 99.8 both inclusive, and the photo acid generator has a weight percent in the range of 0.2 to 25 both inclusive. The above mentioned photoresist produces no extra polymer by side reaction. Thus, the photoresist has high resolution to thereby make it possible to form a fine pattern without resist residue.