Fine motor dysfunction and cognitive impairments commonly develop after stroke, which greatly impact the daily lives of patients. In current occupational therapy, hand dexterity and cognitive functions are evaluated individually (e.g., by manipulation of small objects with fingers, or a paper-and-pencil test), which is insufficient for therapists to grasp the total ability of combined dexterity and cognition in everyday situations. Additionally, the traditional methods require a tester to measure the completion time manually and tend to be monotonous for patients. These problems would be solved using technology. This study aimed to develop a new electric pegboard (e-Peg) prototype and to investigate preliminary utility in healthy adults. The system judges the peg insertion accuracy based on magnetism and records the time course and scores, which are linked to human object manipulation ability. The e-Peg executes three types of tasks: a basic color matching task (BT), a color comparison task using a pattern sheet (CT), and a visual memory task (MT), with one/two-color sample patterns. Six older and nine younger healthy adults performed the e-Peg tasks, functional tests, and responded to questionnaires. As a result, the number of correct answers in a bicolor symmetrical MT were significantly greater in the younger group than in the older group. The older group required a significantly longer completion time for BT and CT than the younger group. Significant correlations were found between one-color BT/CT and dexterity tests, between bicolor BT/CT and dexterity/cognitive tests, and between a bicolor MT and a cognitive test. Questionnaire results revealed that participants regarded BT/CT as easy/interesting tasks, whereas MT was considered a difficult/challenging task. In conclusion, our e-Peg is potentially a useful rehabilitation device that facilitates many tasks related to hand manipulation and attention/executive functions, and a valuable tool for personalized therapy.