Traditional neuroimaging studies have mainly focused on brain activity derived from a simple stimulus and task. Therefore, little is known about brain activity during daily operations. In this study, we investigated hemodynamic changes in the dorsal prefrontal cortex (DPFC) (luring video games as one of daily amusements, using near infrared spectroscopy technique. It was previously reported that oxygenated hemoglobin (oxyHb) in adults' DPFC decreased during prolonged game playing time. In the present study, we examined whether similar changes were observed in children. Twenty children (7-14 years old) participated in our study, but only 13 of them were eventually subject to analysis. They played one or two commercially available video games; namely a fighting and a puzzle game, for 5 min. We used changes in concentration of oxyHb as an indicator of brain activity and consequently, most of the children exhibited a sustained game-related oxyHb decrease in DPFC. Decrease patterns of oxyHb in children during video game playing time did not differ from those in adults. There was no significant correlation between ages or game performances and changes in oxyHb. These findings suggest that game-related oxyHb decrease in DPFC is a common phenomenon to adults and children at least older than 7 years old, and we suggest that this probably results from attention demand from the video games rather than from subject's age and performance.