A shock-absorbing shoe using a spring, the shock-absorbing shoe comprising: a spring configured to provide elastic force to absorb a shock; an outsole forming a sole of the shoe; an upper sole fixed to a top of the outsole and spaced apart from a heel of the outsole to provide a space for installation of the spring, the upper sole descending by a load or ascending by the elastic force of the spring; a lower spring seat formed on a top surface of the outsole to support a lower end of the spring; an upper spring seat formed on a bottom surface of the upper sole to support an upper end of the spring; and an ascent/descent guider configured to rectilinearly guide an ascent/descent of the upper sole wherein the ascent/descent guider comprises: a guide shaft integrally protruding from the lower spring seat to be coaxially arranged with the spring; a shaft holder formed in a hole shape in the upper spring seat to allow the guide shaft to be fitted thereinto, the shaft holder being configured to move in a longitudinal direction of the guide shaft to guide the ascent/descent of the upper sole; and a shaft engagement portion formed on an upper portion of the guide shaft and having a larger outer diameter than the shaft holder, the shaft engagement portion being radially contractible and expandable to be engaged with the shaft holder so as not to be separated when fitted into the shaft holder. a spring configured to provide elastic force to absorb a shock; an outsole forming a sole of the shoe; an upper sole fixed to a top of the outsole and spaced apart from a heel of the outsole to provide a space for installation of the spring, the upper sole descending by a load or ascending by the elastic force of the spring; a lower spring seat formed on a top surface of the outsole to support a lower end of the spring; an upper spring seat formed on a bottom surface of the upper sole to support an upper end of the spring; and an ascent/descent guider configured to rectilinearly guide an ascent/descent of the upper sole wherein the ascent/descent guider comprises: a guide shaft integrally protruding from the lower spring seat to be coaxially arranged with the spring; a shaft holder formed in a hole shape in the upper spring seat to allow the guide shaft to be fitted thereinto, the shaft holder being configured to move in a longitudinal direction of the guide shaft to guide the ascent/descent of the upper sole; and a shaft engagement portion formed on an upper portion of the guide shaft and having a larger outer diameter than the shaft holder, the shaft engagement portion being radially contractible and expandable to be engaged with the shaft holder so as not to be separated when fitted into the shaft holder. a guide shaft integrally protruding from the lower spring seat to be coaxially arranged with the spring; a shaft holder formed in a hole shape in the upper spring seat to allow the guide shaft to be fitted thereinto, the shaft holder being configured to move in a longitudinal direction of the guide shaft to guide the ascent/descent of the upper sole; and a shaft engagement portion formed on an upper portion of the guide shaft and having a larger outer diameter than the shaft holder, the shaft engagement portion being radially contractible and expandable to be engaged with the shaft holder so as not to be separated when fitted into the shaft holder.