A running analysis device comprising: an analyzer that analyzes running of a user using sensor data output from a sensor attached to the user, wherein the sensor includes an acceleration sensor that outputs an acceleration signal, the analyzer includes an indicator identifying unit that identifies landing timings and leaving timings on the basis of the data of accelerations in respective axes, identifies stance phases and swing phases of the right leg and the left leg on the basis of the identified landing timings and leaving timings, and identifies, in a swing phase in a running cycle, a period that serves as an indicator for increasing the running speed; and the analyzer analyzes the running of the user based on the period identified by the indicator identifying unit, wherein the indicator identifying unit identifies (i) a backward swing period in which a leg of the user swings back and (ii) a forward swing period in which the leg of the user swings forward, the backward swing period and the forward swing period being included in the swing phase, as the period serving as the indicator for increasing the running speed; and the indicator identifying unit identifies the backward swing period and the forward swing period based on the acceleration signal as the sensor data; characterized in that the acceleration sensor outputs at least an acceleration signal in a vertical direction as the sensor data, and the indicator identifying unit obtains a height position waveform showing a height position of the acceleration sensor by integrating the acceleration signal twice, takes a timing at which the height position waveform shows a local minimum value as a most sinking timing of the user, and takes, of the swing phase, a period until the most sinking timing as the backward swing period and a period since the most sinking timing as the forward swing period, or the acceleration sensor outputs at least an acceleration signal in a front-back direction and an acceleration signal in a vertical direction as the sensor data, and the indicator identifying unit extracts the sensor data of a section in which the user speeds up in a moving direction, takes a timing at which a sum of a square of a value of an acceleration in the front-back direction and a square of a value of an acceleration in the vertical direction is largest in the section as a maximum kick timing, and takes, of the swing phase, a period until the maximum kick timing as the backward swing period and a period since the maximum kick timing as the forward swing period. an analyzer that analyzes running of a user using sensor data output from a sensor attached to the user, wherein the sensor includes an acceleration sensor that outputs an acceleration signal, the analyzer includes an indicator identifying unit that identifies landing timings and leaving timings on the basis of the data of accelerations in respective axes, identifies stance phases and swing phases of the right leg and the left leg on the basis of the identified landing timings and leaving timings, and identifies, in a swing phase in a running cycle, a period that serves as an indicator for increasing the running speed; and identifies landing timings and leaving timings on the basis of the data of accelerations in respective axes, identifies stance phases and swing phases of the right leg and the left leg on the basis of the identified landing timings and leaving timings, and identifies, in a swing phase in a running cycle, a period that serves as an indicator for increasing the running speed; and the analyzer analyzes the running of the user based on the period identified by the indicator identifying unit, wherein the indicator identifying unit identifies (i) a backward swing period in which a leg of the user swings back and (ii) a forward swing period in which the leg of the user swings forward, the backward swing period and the forward swing period being included in the swing phase, as the period serving as the indicator for increasing the running speed; and the indicator identifying unit identifies the backward swing period and the forward swing period based on the acceleration signal as the sensor data; characterized in that the acceleration sensor outputs at least an acceleration signal in a vertical direction as the sensor data, and the indicator identifying unit obtains a height position waveform showing a height position of the acceleration sensor by integrating the acceleration signal twice, takes a timing at which the height position waveform shows a local minimum value as a most sinking timing of the user, and takes, of the swing phase, a period until the most sinking timing as the backward swing period and a period since the most sinking timing as the forward swing period, or the acceleration sensor outputs at least an acceleration signal in a front-back direction and an acceleration signal in a vertical direction as the sensor data, and the indicator identifying unit extracts the sensor data of a section in which the user speeds up in a moving direction, takes a timing at which a sum of a square of a value of an acceleration in the front-back direction and a square of a value of an acceleration in the vertical direction is largest in the section as a maximum kick timing, and takes, of the swing phase, a period until the maximum kick timing as the backward swing period and a period since the maximum kick timing as the forward swing period.