Abstract: Provided are a wearable instrument and other things capable of setting suitable tightness. A wearable device includes the following: a collar; a belt having one end connected to the collar, and extending to the animal's back via a dog's armpit when the wearable device is attached to the dog; and a joint where the belt length is adjusted. The belt has a wearable-device index indicated for the length adjustment with the joint, the wearable-device index corresponding to a measuring-instrument index indicated on an index belt included in a measuring instrument.

Abstract: A wearable instrument is provided that measures biological information over an extended period of time by enabling an electrode to be readily pressed to an axilla of an animal. The wearable instrument includes: electrodes to be placed under the left and right axillae of a dog to produce an electrocardiogram; pull-up straps to be placed in direct contact with the axilla to press the electrodes onto the axilla; and a cinch strap placed across the anterior chest of the dog to draw the left and right sections of the pull-up strap together.