Disclosed is a positive photoresist composition comprising (A) a compound capable of generating an acid upon irradiation with actinic rays or radiation and (B) a resin capable of decomposing under the action of an acid to increase the solubility in alkali, containing a repeating unit having a group represented by the following formula (I): wherein R1 represents hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, which may have a substituent, R1 to R7, which may be the same or different, each represents hydrogen atom, an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent or an alkenyl group which may have a substituent, provided that at least one of R6 and R7 is a group exclusive of hydrogen atom and R6 and R7 may combine to form a ring, and m and n each independently represents 0 or 1, provided that m and n are not 0 at the same time. The positive photoresist composition can further comprise a fluorine-containing and/or silicon-containing surfactant and at least one first solvent selected from propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate and 3-ethoxypropionate.