noun
pedometer; step counter
A device that counts the number of steps a person takes. The term is a registered trademark in Japan, but is widely used generically.
健康のために万歩計を毎日つけている。
I wear a pedometer every day for my health.
万歩計の数字を見て、もっと歩こうと
Seeing the number on the pedometer, I decided to walk more.