An information processing system comprising: at least one operating portion (250, 260) configured to be operated by a user; a device carried by the user and comprising: an inertial sensor (114, 115); an image capturing section; and a detection target portion (205, 205a) configured to be captured by the image capturing section, the detection target portion being operationally connected to the at least one operating portion to move in conjunction with the operation portion, the detection target portion configured to move along a predetermined movement path in accordance with the operation; the information processing system further comprising an information processing apparatus operationally connected to the inertial sensor and the image capturing section, comprising: a processing section (81, S148, S134) for performing a first process that is information processing; a detection section for detecting a detection target portion image representing the detection target portion comprised in a captured image captured by the image capturing section; a specifying section for specifying at least one of a position and a shape of the detection target portion image in the captured image; a determination section (81, S148) for, based on the at least one of the position and the shape of the detection target portion image in the captured image, determining whether or not a condition for performing the first process is satisfied; and a change section (81, S141-S147) for changing the condition based on data output from the inertial sensor, wherein, at least when the detection target portion image in the captured image is located in at least one of a predetermined position and a predetermined range based on the movement path, the determination section determines that the condition for performing the first process is satisfied, and characterized in that the change section changes the at least one of the predetermined position and the predetermined range based on the data output from the inertial sensor, thereby changing the condition. at least one operating portion (250, 260) configured to be operated by a user; a device carried by the user and comprising: an inertial sensor (114, 115); an image capturing section; and a detection target portion (205, 205a) configured to be captured by the image capturing section, the detection target portion being operationally connected to the at least one operating portion to move in conjunction with the operation portion, the detection target portion configured to move along a predetermined movement path in accordance with the operation; an inertial sensor (114, 115); an image capturing section; and a detection target portion (205, 205a) configured to be captured by the image capturing section, the detection target portion being operationally connected to the at least one operating portion to move in conjunction with the operation portion, the detection target portion configured to move along a predetermined movement path in accordance with the operation; the information processing system further comprising an information processing apparatus operationally connected to the inertial sensor and the image capturing section, comprising: a processing section (81, S148, S134) for performing a first process that is information processing; a detection section for detecting a detection target portion image representing the detection target portion comprised in a captured image captured by the image capturing section; a specifying section for specifying at least one of a position and a shape of the detection target portion image in the captured image; a determination section (81, S148) for, based on the at least one of the position and the shape of the detection target portion image in the captured image, determining whether or not a condition for performing the first process is satisfied; and a change section (81, S141-S147) for changing the condition based on data output from the inertial sensor, wherein, at least when the detection target portion image in the captured image is located in at least one of a predetermined position and a predetermined range based on the movement path, the determination section determines that the condition for performing the first process is satisfied, and characterized in that a processing section (81, S148, S134) for performing a first process that is information processing; a detection section for detecting a detection target portion image representing the detection target portion comprised in a captured image captured by the image capturing section; a specifying section for specifying at least one of a position and a shape of the detection target portion image in the captured image; a determination section (81, S148) for, based on the at least one of the position and the shape of the detection target portion image in the captured image, determining whether or not a condition for performing the first process is satisfied; and a change section (81, S141-S147) for changing the condition based on data output from the inertial sensor, wherein, at least when the detection target portion image in the captured image is located in at least one of a predetermined position and a predetermined range based on the movement path, the determination section determines that the condition for performing the first process is satisfied, and characterized in that the change section changes the at least one of the predetermined position and the predetermined range based on the data output from the inertial sensor, thereby changing the condition.